Opinion for the Court filed by Circuit Judge WILLIAMS.
Aрpellants Coalition on Sensible Transportation (“COST”) and other groups
1
bring a number of challenges concerning a road construction project in Montgomery County, Maryland. The project will widen approximately sixteen miles of Interstate 270 (“1-270”) and modify five interchanges along the way; it is expected to take five years and cost more than $113 million. COST claims that various federal, state, and local officials
2
violated § 4(f) of the Department of Transportation Act, 49 U.S.C. § 303(c) (1982), the procedural requirements of § 102(2)(C) of the National Environmental Policy Act, 42 U.S.C. § 4332(2)(C) (1982), and the hearings requirement of § 128 of the Federal-Aid Highway Act, 23 U.S.C. § 128 (1982). It also contends that the district court erred in refusing to consider certain evidence and in denying a discovery request. The court below granted summary judgment for the defendants.
Coalition on Sensible Transportation v. Dole,
I. Section 4(f) Issues
The stretch of 1-270 at issue runs north from the Spur connecting 1-270 to 1-495 (the Washington Beltway). It is a heavily travelled route for traffic entering and leaving the District of Columbia and also for local traffic between and within the various nearby towns. Traffic conditions in this area are congested, and unchallenged administrative findings indicate that the population growth anticipated in the coming years is likely to add to the congestion. See Joint Appendix (“J.A.”) vol. 3, 3-4, 6-7. Among the amenities of the area are its parks, several of which are presently bordered or crossed by 1-270. These parks will be affected by the proрosed widening.
Under § 4(f) of the Department of Transportation (“DOT”) Act, the Secretary may approve a use of significant public park land 3 only if “(1) there is no prudent and feasible alternative to using that land; and (2) the program or project includes all possible planning to minimize harm to the park ... resulting from the use.” COST brings essentially three challenges to the district court’s decision. It contests (1) the court’s findings that the 1-270 project’s effect on parks did not amount to a statutory “use”; *63 (2) the court’s acceptance of DOT’S conclusions that there was no prudent and feasible alternative within the meaning of § 4(f)(1); and (3) its acceptance of DOT’S conclusion that harm to the parks could not have been minimized by adoption of a rejected alternative. We agree with plaintiffs’ view of what constitutes a park use, but reject their claim that DOT neglected its § 4(f) duties.
A. Use of Parklands Under § 4(f)
Before analyzing the adequacy of the administrative § 4(f) analysis, the district court found that the effects of the 1-270 project on adjacent land were too insubstantial to amount to a “use” within the meaning of § 4(f).
At issue are four parks — Cabin John Regional Park, Middlebrook Hill Neighborhood Conservation Area, Metropolitan Grove Road Park, and Seneca Creek State Park. In none of the four are there popular facilities in the immediate vicinity of the highway, and the expansion project seems unlikely to change this state of affairs. In each park the expansion plan calls for “temporary constructiоn easements,” narrow strips of parkland adjacent to the roadway. The topography will be graded to facilitate use in the construction project, leaving slopes along the edge of the highway; at the conclusion of the project, these strips, landscaped and revegetated, will be returned to their governmental owners. The district court characterized the uses as temporary and sought to apply “constructive use” cases that made the finding of a § 4(f) use contingent on “substantial” harm.
Sierra Club v. Dep’t of Transportation,
In the circumstances of this case, it hardly seems necessary to explore the nuances of “constructive uses.” The 1-270 project is expected to last five years and to change about ten acres of parkland permanently. This is enough. The encroachment during the construction period might be a sufficiently substantial harm to trigger § 4(f) despite its temporary nature, but we need not decide this in view of the permanent changes. These take two forms. First, the project will remove 50-year-old oaks that will take two generations to replace; as man measures time, this is permanent. Second, the parks’ topography will be altered, presumably forever. The appellees seek to undercut the permanence of the changes by pointing to the promise of mitigation measures at the end of the project. While these bear on the satisfaction of § 4(f)(2)’s requirement that harms be minimized, they do not help in determining whether a use exists.
This is not to say that every change within park boundaries constitutes a use. For example, in
Sierra Club v. Dep’t of Transportation,
the court considered whеther permitting limited commercial jet landings in an airport in Grand Teton National Park amounted to a use triggering § 4(f). The agency had determined that the change would result in a cumulative noise increase that was not significant.
Despite its viewpoint on the use question, the district court proceeded to a careful review of the administrative § 4(f) find *64 ings and found no violation of the statute. We agree and in the two sections below address the claims based on § 4(f)(1) and § 4(f)(2).
B.
Feasible and Prudent Alternatives
Before the Secretary approves a park use, he must under § 4(f)(1) find that there is no feasible and prudent alternative to use of protected lands. Here at least one alternative is concededly feasible, but DOT contends that none is prudent. In
Citizens to Preserve Overton Park v.
Volpe,
DOT and the other appellees concede that the use of construction easements for the 1-270 project could have been avoided entirely through the use of retaining walls. Appellees do not argue that the cost of these retaining walls would have reached “extraordinary magnitudes,” though our calculations indicate they are by no means cheap: $7,901,000. Nor do appellees argue that the retaining walls would cause any community disruption.
Overton Park,
Unlike the usual park-or-concrete choice pоsed by a § 4(f) decision, the judgment here was essentially aesthetic. The DOT determination noted that the retaining walls of the alternative would be “long and high.” J.A. vol. 2, N, 2. At oral argument it was asserted without contradiction that some would have reached 50 feet in height. At such points, a park user would look 50 feet down onto the highway. Highway users would have faced high walls for considerable stretches; so would park users, in those areas where the park surface was below the highway. DOT could well have regarded the results as grotesque. In the selected alternative, by contrast, regrading, reseeding and reforestation were possible and would produce “a similar edge of the park as exists today.” Id. See also J.A. vol. 4, VII-4 to 7. In essence, the officials charged with the task concluded that the “use” alternative would do less harm to park values than would nominal “non-use.” Bearing in mind the concern for preservation of parklands at the core of § 4(f), we think the facts here qualify as “truly unusual.” 5
COST argues that there is inadequate record support for the key aesthetic judgment. Reply Brief for Appellants at 4. We disagree. Aesthetic determinations under § 4(f) do not require a ponderous record. Resolution of such issues requires little or no quantitative data. Of course we must assure ourselves that the aesthetic determination was made seriously and not merely as a pretext to circumvent § 4(f). Here the record indicates a serious consideration of the appropriate factors; there is no allegation of bad faith or impropriety, nor, so far as we can find, any clue to such behavior. In such circumstances “the court is not empowered to substitute its judgment for that of the agency.”
Over-
*65
ton Park,
COST points out that the Department of Interior supported retaining walls. See J.A. vol. 4, IX-6. While this is relevant, it cannot be determinative: Congress vested the § 4(f) decision in the Secretary of Transportation. Moreover, we note that local park officials, presumably no less sensitive than Interior and much more immediately concerned, supported the construction easement choice. J.A. vol. 4, IX-12, -27, -81, -42 to 43. Finally, we reject COST’S suggestion that DOT erred in considering the comparative visual impacts on motorists. While highway users’ interests in speed and convenience of transportation are not within the ambit of § 4(f) protection, their aesthetic interests surely are. In short, we see no indication of an abuse of discretion.
C. Minimization of Harm
Besides lacking feasible and prudent alternatives, a transportation project using protected lands must under § 4(f)(2) include “all possible planning to minimize harm.” The chosen version of the 1-270 project provides for mitigation in the form of revegetation and landscaping. J.A. vol. 4, VII-9. The final plans also included construction of small retaining walls in Cabin John Regional Park and Seneca Creek State Park. See J.A. vol. 2, N, 3. COST argues, however, that the § 4(f)(2) determination was inadequate, because the immediate predecessor to the final plan would have inflicted less harm on the park-lands.
In response to community objections, the responsible officials adopted the prevailing plan from its predecessor simply by shifting part of the roadbed 24 feet to the west. The realignment reduced impacts on сertain residences, completely avoided an anticipated encroachment onto Tilden Park, and slightly increased the encroachment onto Cabin John Regional Park. J.A. vol. 2, N,
2;
vol. 4, VII-4 to 5. The district court found that the penultimate and ultimate alignments would cause substantially equal damage and that the responsible officials were therefore free to choose between them.
Section 4(f)’s requirement that harm be minimized does not constrain the Secretary’s choice between two plans causing substantially equal damage to § 4(f) values.
See Druid Hills Civic Ass’n v. Federal Highway Administration,
So far as park values are concerned, the two plans vary trivially. The selected alternative will use an additional half acre of Cabin John Regional Park, but the resulting increment of harm is negligible. See J.A. vol. 4, VII-2 (closest park facility to 1-270 is a trail that comes within 300 feet of the highway); Plate 10 (illustrating location of construction easements). The predecessor would have entailed a small (.1 acre) encroachment in Tilden Park, which under the selected alternative is untouched. The differences in the harms from the two competing alternatives are so small that it *66 was reasonable to consider them substantially equivalent. 7
COST again contends that there is inadequate support for the determination. It is true that there is no formal determination of the equivalence of the harms at issue, but formal findings are not required in a § 4(f) determination.
Overton Park,
II. NEPA Claims
COST also contends that the responsible officials were obliged to prepare an environmental impact statement (“EIS”) under the terms of § 102 of the National Environmental Policy Act (“NEPA”), 42 U.S.C. § 4332 (1982). This provision applies to “major Federal actions significantly affecting the quality of the human environment” and requires “a detailed statement” on
(i) the environmental impact of the proposed action,
(ii) any adverse environmental effects which cannot be avoided should the proposal be implemented,
(iii) alternatives to the proposed action,
(iv) the relationship between local short-term uses of man’s environment and the maintenance and enhancement of long-term productivity, and
(v) any irreversible and irretrievable commitments of resources which would be involved in the proposed action should it be implemented.
An exception to this requirеment applies when a less comprehensive environmental review, or environmental assessment (“EA”), provides a basis for a finding of no significant impact (“FONSI”).
See
40 C.F.R. § 1501.4(b), (c), & (e) (1986) (describing process);
id.
§ 1508.9 (defining EA);
id.
§ 1508.13 (defining FONSI);
Sierra Club,
The NEPA process involves an almost endless series of judgment calls. Here we consider ones relating to the detail in which specific items should be discussed and the agencies’ treatment of the project’s relation to other government activities. It is of course always possible to explore a subject more deeply and to discuss it more thoroughly. The line-drawing decisions necessitated by this fact of life are vested in the agencies, not the courts. The latters’ “role ... is simply to ensure that the agency has adequately considered and disclosed the environmеntal impact of its actions and that its decision is not arbitrary or capricious.”
Baltimore Gas & Electric Co. v. Natural Resources Defense Council, Inc.,
In examining decisions not to prepare an EIS, we consider four factors:
First, the agency must have accurately identified the relevant environmental concern. Second, once the agency has identified the problem it must have taken a “hard look” at the problem in preparing the EA. Third, if a finding of no significant impact is made, the agency must be able to make a convincing case *67 for its finding. Last, if the agency does find an impact of true significance, preparation of an EIS can be avoided only if the agency finds that changes or safeguards in the project sufficiently reduce the impact to a minimum.
Sierra Club,
COST relies on these standards in making three general challenges. First, it alleges that the appellees failed to take a hard look at or make the requisite findings regarding impacts on traffic, development, wildlife habitat, and wetlands. Second, it charges that the project was impermissibly segmented. Third, it challenges the district court’s findings concerning cumulative significance. We consider each of these challenges in the subsections below.
A. Impacts on Traffic, Development, Wildlife Habitat and Wetlands
According to the FONSI, traffic conditions on 1-270 are presently extremely congested, and development is expected to continue in the area. J.A. vol. 4, III — 1 to 3, Plate 8. COST alleges that defendants never gave the 1-270 project’s impact on traffic patterns in the region the requisite hard look or found them to be insignificant.
We disagree. It is evident from the record that, just as one would expect where a road project was at issue, the traffic aspect of the plan received a hard look. Projections of traffic volume for the “design year” of 2010 were derived from development projections from various sources. See J.A. vol. 2, T, 2; vol. 3, 3-4; vol. 4, VIII-72. The EA and FONSI demonstrate careful attention to the present traffic conditions at interchanges and connecting roads and the effects of the project on these roads. Id. vol. 2, T, 3-4; vol. 3, 3-4, 31-45; vol. 4, Plate 8. Certain improvements, including ones to the Capital Beltway, were assumed as part of the study, and with these improvements the connecting roads were anticipated to perform adequately in the design year. Id. vol. 2, T, 2-4, V, 2-3; vol. 4, VIII-22, -24, -30 to 31.
COST’S contentions to the contrary аmount at most to technical disputes of the sort most fit for expert administrative resolution and judicial deference.
See Baltimore Gas & Electric Co.,
More interesting are COST’S suggestions that the review documents overlooked the tendency of the project itself to generate traffic increases, both by attracting development to the area and by inducing some persons to make journeys that otherwise would not be made at all. See Brief for Appellants at 24. The EA and FONSI both predict that more cars will use 1-270 itself under the “Build” than under the “No-Build” alternative, see J.A. vol. 3, 51; vol. 4, Plate 8, so there can be no claim that the appellees were blind to the prospect of the impact at issue. The dispute is about the cause of the increase. The responsible officials concluded that the project’s partial cure of congestion on 1-270 would lure additional travelers away from other roads, until a new equilibrium (with less aggregate congestion) was established. J.A. vol. 3, iv, 31-32. Responding specifically to comments at a public hearing that the improvement would “facilitate excessive levels of development,” the FONSI replied that the region’s development levels were constrained by “local and secondary roads,” id. vol. 4, VIII-72, i.e., not primarily by the condition of 1-270. It alsо noted that its traffic projections were based on *68 development levels estimated by local and county agencies. Id.
Plaintiffs contest these findings solely with generalities. They note that it is “well established in traffic engineering that travel demand is a function of the adequacy of the road system,” pointing to decisions to reduce shopping trips, for example, on account of traffic. J.A. vol. 1, G, 9. Similarly they observe that it is “commonly recognized that ... increased highway capacity will induce further development.” Id., H, 5-6.
The appellees’ analysis is not arbitrary and capricious. COST fights it with truisms, but makes no effort to establish that this project itself will generate major development or net traffic increments {i.e., increments exceeding relief elsewhere). Given the lengthy process of consultation with the localities affected, the documentation by the responsible officials of the effects in general, and the officials’ plausible thesis as to the project’s role in regional development, we find that the officials made a sufficiently convincing case for dispensing with an EIS in which to explore in detail the likelihood and scope of these effects.
Our conclusion is quite consistent with
Appalachian Mountain Club v. Brinegar,
Nor did the EA slight the project’s impacts on wildlife hаbitat and wetlands along the right of way. The EA characterized the areas within the existing right-of-way fence as being of “marginal use as wildlife habitat,” a statement of obvious and literal truth. J.A. vol. 3, 56. It noted that even areas beyond the fence had less habitat value than they would in undeveloped areas. Id. This conclusion is supported by a 15-page study of these impacts. J.A. vol. 2, G. In its reply brief at 12-13, COST for the first time takes issue with the second statement, characterizing it as one that would invariably excuse failure to analyze destruction near an existing highway. But plaintiffs point neither to any defects in the underlying study nor to any other fact drawing the final determination into question. We do not find it arbitrary or capricious.
B. Project Segmentation
COST asserts that the scope of the 1-270 project was improperly defined for NEPA purposes. Agencies mаy not evade their responsibilities under NEPA by artificially dividing a major federal action into smaller components, each without “significant” impact.
Taxpayers Watchdog, Inc. v. Stanley,
(1) Connects logical termini and is of sufficient length to address environmental matters on a broad scope;
(2) Has independent utility or independent significance, i.e., is useable and a reasonable expenditure even if no additional transportation improvements in the area are accomplished; and
(3) Will not restrict consideration of alternatives for other reasonably foreseeable transportation improvements.
23 C.F.R. § 771.111(f) (1987). A number of courts have relied on the same or closely similar factors in their segmentation determinations.
See, e.g., Taxpayers Watchdog,
In COST’S view, the scope of the EA and FONSI should have been extended to include the Spur connecting 1-270 to the Capital Beltway and certain interchange *69 projects along the route. We address these in turn.
COST maintains that the Beltway was the only logical terminus of the project. First, however, we note that in the context of a highway within a single metropolitan area — as opposed to projects joining major cities — the “logical terminus” criterion is unusually elusive. Thus we join the court in
Piedmont Heights Civic Club,
COST suggests that because the interchange projects at MD 189, MD 124/117, and 1-370 will facilitate traffic movement along the 1-270 corridor, they have little independent utility or independent significance apart from the 1-270 project, and should therefore have been examined in the same EA. Brief for Appellants at 33-34. But it is inherent in the very concept of a highway network that each segment will facilitate movement in many others; if such mutual benefits compelled aggregation, no project could be said to enjoy independent utility. The proper question is whether one project will serve a significant purpose even if a second related project is not built.
See Taxpayers Watchdog, Inc.,
COST further claims that the 1-270 widening will restrict consideration of alternatives for related projects. Like the mutual-benefit argument considered above, the statement is always true to a degree; future road projects will have to take into account the traffic facilitated by any given project. This is not enough by itself to render a FONSI inadequate. Only when a given project effectively commits decision-makers to a future course of action will this form of linkage argue strongly for joint environmental evaluation.
See National Wildlife Federation,
Such a commitment could occur for either of two reasons. First, a project might appear to be an unreasonable expenditure of funds unless some related project were *70 also completed. See 23 C.F.R. § 771.-111(f)(2). But once the project was itself completed, its costs would be sunk, and presumably highway officials would not proceed with the second merely to vindicate their decision on the first. Second, completion of the first project may cause the benefit/cost ratio on the second to rise sharply. Thus if a two-lane road between two cities is widened to four lanes for half its length, the return from investment in completion of the project may be usually favorable and its approval by rational decisionmakers foreordained. Here, however, we see no evidence that completion of I-270 would compel adoption of any of the interchange projects. 8
C. Cumulative Impact
A separate but related claim is that the defendants failed to analyze the cumulative impact of the project together with those of various related interchange and Spur improvements. Of course one might view this argument as simply a replay of the improper-segmentation argument already considered. Council on Environmental Quality (“CEQ”) regulations, however, provide a distinct meaning to the concept. They define cumulative impact as “the incremental impact of the action [at issue] when added to other past, present, and reasonably foreseeable future actions____” 40 C.F.R. § 1508.7. See also id § 1508.-27(b)(7) (cumulative significance discussed as one of ten factors to be considered in gauging intensity for purposes of determining significance). We believe the defendants followed the approach indicated by the regulations. 9
There are nine existing or planned interchanges within the affected stretch of I-270. Five interchange projects (at Montrose Road, MD 28, Middlebroоk Road, MD 118, and MD 121) were considered part of the 1-270 project and evaluated together with the road widening in the same EA and FONSI. Interchanges at four other locations (MD 189, Shady Grove Road, I-370, and MD-124-117) were planned before the I-270 project, and although discussed in the EA and FONSI, received detailed treatment only in other EA’s, FONSI’s and EIS’s. See J.A. vol. 2, R, 2-5. Beyond the 1-270 project’s limits, previously approved improvements to the Spur which links I-270 and the Capital Beltway were also considered as part of the background in the EA and FONSI. Id. T, 2-4, V, 2-3. COST contends appellees should have assessed the cumulative impacts of the MD 189, I-370, MD 124-117 and Spur projects in greater detail. See Reply Brief for Appellants at 14 n. 21.
We think this misconceives both the CEQ regulation and the purpose of NEPA. It makes sense to consider the “incremental impact” of a project for possible cumulаtive effects by incorporating the effects of other projects into the background “data base” of the project at issue, rather than by restating the results of the prior studies.
Piedmont Heights Civic Club, Inc. v. Moreland,
COST quotes the following language of
Kleppe v. Sierra Club,
III. Section 128 Claims
Under § 128 of the Federal-Aid Highways Act, 23 U.S.C. § 128 (1982), public hearings must be held prior to approval of certain highway projects. 11 COST raises two different challenges in connection with this statute. Brief fоr Appellants at 36-37. First, it argues that the public hearing held on February 15, 1984 was inadequate because of NEPA violations. Second, it claims that a shift in alignment made in response to issues raised at this hearing required another hearing. As we have explained, we find no NEPA violations, and thus we see no merit in the first of these arguments.
As for the second, we agree with the district court that project changes made after a § 128 hearing require a new hearing only if those changes are substantial or significant.
V. Discovery Issues
COST’S final argument 12 is that the district court improperly denied it opportunity for discovery. Although COST was vague as to what its discovery would entail, it indicated that it would seek evidence from the defendants tending to show that they failed to consider significant impacts. Tr., April 18, 1986, at 8-9. On appeal, it argues that Fed.R.Civ.P. 26(b)(1), which governs the usual scope of discovery, requires that it be permitted to investigate such matters.
As the district court observed, ordinarily “the focal point for judicial review should be the administrative record already in existence, not some new record made initially in the reviewing court.”
Camp v. Pitts,
COST relies on
Committee for Nuclear Responsibility, Inc. v. Seaborg,
CONCLUSION
Evaluating environmental effects of major roadbuilding projects and adequately explaining the various choices made is a long and arduous process, as is reviewing such determinations. It is unlikely that any such undertaking will ever be absolutely flawless; perfection is elusive. We do not think the process was flawless here. However, after carefully examining each objection to the various administrative findings and explanations, we are persuaded that the appellees satisfied all statutory requirements. Accordingly, the judgment of the district court is
Affirmed.
Notes
. Other appellants are the North Bethesda Congress of Citizens Associations, the Sierra Club, and the Washington Area Bicyclists Association. References to COST or plaintiffs include these groups.
. The defendants were Elizabeth Dole, Secretary of Transportation, and Ray Bainhart, Administrator of the Federal Highway Administration. Defendant-intervenors were Hal Kassoff, Administrator of the Maryland State Highway Administration; the City of Gaithersburg, Maryland; and the Mayor and Council of Rockville, Maryland. These parties adopt a united front in a single brief on appeal. We refer to them collectively as defendants, appellees or the responsible officials.
. The significance of the park land affected by the project is conceded by appellees.
. It is worth noting that the final plan does make use of retaining walls to avoid encroaching on Rockmead Park. J.A. vol. 3, at 79-80.
. The Overton Park standard is rephrased in 23 C.F.R. § 771.135(a)(2) (1987) (emphasis added) as follows:
Supporting information must demonstrate that there are unique problems or unusual factors involved in the use of alternatives and that the cost, environmental impacts, or cornmunity disruption resulting from such alternatives reaches extraordinary magnitudes.
This regulation changes an “or" in Overton Park to the italicized “and,” arguably establishing a higher hurdle to use of § 4(f) lands. The Council on Environmental Quality’s power to overrule an authoritative Supreme Court interpretation is of course dubious. In any event, we are confident that the regulation’s extra requirement should not be applied where it would fail to serve the statutory purposes.
. The
Overton Park
standard of review obviously applies to district courts, but its application to appellate courts is unclear. Some appeals courts have held that no particular deference is appropriate in reviewing § 4(f) determinations, since the district court’s conclusions are based on the same administrative record that is before the appellate court.
See Druid Hills Civic Ass’n
v.
Federal Highway Administration, 772
F.2d 700, 714 (11th Cir.1985):
Stop H-3 Ass’n v. Dole,
. Tilden Park is about 79 acres, while Cabin John is about 525 acres. Of these totals, by our calculations, Tilden would have lost slightly over one percent, while Cabin John will lose slightly less than one percent.
. COST relegates to a footnote its fallback argument that at least a programmatic EIS should have been prepared. Brief for Appellants at 35 n. 23. Such an EIS is appropriate where the connected, cumulative or sufficiently similar character of actions is such that it is "the best way” to assess their combined impacts.
Foundation on Economic Trends v. Heckler,
. COST also suggests that the combination of insignificant impacts mentioned in the EA should have received separate consideration as a cumulative impact. Brief for Appellant at 28. It concedes, however, that the CEQ cumulative impact regulations are directed at impacts caused by combining the project in contemplation with other projects, Reply Brief for Appellants at 14 n. 20, the topic discussed in the text. Insofar as COST’S claim calls for some explicit aggregation of impacts identified in an EA, we see no need for such a summary. COST makes no claim of synergistic effects.
. In fact, COST’S quote omits “are currently pending before an agency.” See Brief for Appellants at 29.
. Section 128(a) provides in part:
Any State highway department which submits plans for an Intеrstate System project shall certify to the Secretary that it has had public hearings at a convenient location, or has afforded the opportunity for such hearings, for the purpose of enabling persons in rural areas through or contiguous to whose property the highway will pass to express any objections they may have to the proposed location of such highway.
. COST has also challenged the district court's decision to strike portions of the affidavits of its experts. We think the district court erred in striking some of these affidavits, which were relevant to the significance of traffic impacts. However, after closely examining the evidence under the standards that the district court would have applied, we are certain that the error was harmless.
. In Seaborg, the government’s brief failed to offer any argument opposing discovery. Brief for the Appellees (No. 71-1732).
