OPINION
The United States District Court for the Northern District of West Virginia suppressed evidence critical to the racketeering prosecution of defendant-appellee Cyrus Jonathan George. We reverse in part, vacate in part, and remand.
I.
Dallas P. Rice was shot near his secluded trailer home in Ten Mile, Upshur County, West Virginia, shortly after 5 p.m. on November 14, 1986. See App. at 206-09. Rice’s trailer home was accessible by two roads — a main dirt road and Calico Road, a one-lane dirt road that could be traversed only by four-wheel drive vehicles. Upon arrival at the scene of the shooting, county police, including sheriff Fred Gaudet and deputy Lewis Anderson, determined that the shots had been fired from an area of freshly cut brush atop a cliff approximately 100 yards behind the clearing where Rice had been standing when he was shot. See id. at 222. The police also concluded that Calico Road had not been recently traveled and that the main road to Rice’s trailer home had been traveled only by Rice’s neighbors. See id. at 221.
When Gaudet and á county officer drove up Calico Road approximately 1 — IV2 hours later, they broke through the ice that was covering numerous mudholes due to the recent freeze. Officers dispatched to block off the other end of Calico Road also found iced-over mudholes, confirming that no vehicle had recently exited the area via the road. See id. at 254-56. After driving a quarter mile on Calico Road, Gaudet discovered an area near the road where a vehicle had been parked. See id. at 255-56. Police with bloodhounds had followed a different quarter-mile trail to this same location from the site of the shooting. See id. at 239, 269. As Gaudet drove beyond this spot, he discovered that a vehicle driving in the same direction had already broken through the ice covering the mudholes in the road. See id. at 256. Proceeding along the road, Gaudet encountered defen *1115 dant-appellee Cyrus Jonathan George driving toward him in a four-wheel drive truck. See id. at 256-57. 1 George was stopped by the police, and before they could interrogate him, George spontaneously said, “I don’t have any guns. Go ahead and search my truck, I give you my permission,” and “I didn’t hear any shots.” Id. at 258, 259; see also id. at 276. (George claimed to be tracking a bear. See id. at 260.) George also admitted to the police that he had been “parked ... earlier looking at the river.” Id. Gaudet searched George’s truck and found a tool box, but no gun. See id. at 262-63. The police did not arrest George. See id. at 264.
George agreed to take polygraph and paraffin tests, see id. at 260-61, 276, and Gaudet asked him to drive back to the other end of Calico Road, see id. at 243. When George arrived at the end of Calico Road, however, he told the officer who met him that he would not take the tests. See id. at 261, 265. The police thereafter took photographs of George and his truck. See id. at 264. These photographs showed that George’s knees and the back of his pants were damp and that he was wearing boots. See id. at 277. The police also photographed tire tracks near the crime scene. See id. at 270.
As the investigation of the Rice shooting continued in the days following, the police found, assorted evidence in and around the Calico Road area. They recovered a cardboard box labeled “Remington. Shells,” some .30/30 shells, and parts of a gun that had been sawed into small pieces. Near where George had parked his truck, police recovered the receiver of a Winchester Model 94 .30/30 lever-action rifle. See id. at 228-29, 234-35, 241, 279. A trace of the serial number found on the receiver disclosed that the gun had been purchased by George on August 10, 1973. See id. at 233-34. The police also recovered half a hacksaw blade from the river, metal shavings, cloth fragments, paper towels, and scraps of black electrician’s tape. See id. at 228-31, 238-39, 242. 1
On February 3, 1987, someone shot at Sheriff Gaudet. The bullet missed Gaudet and lodged in his car. See id. at 119-20. (George knew at this time that he was under investigation for the Rice shooting. See id. at 114.) The next day, after a meeting with the state prosecutor, county police decided to obtain arrest and search warrants for George in connection with the Rice shooting. See id. at 106-07. Testimony revealed that the police had felt an “urgency” to procure the search warrants following the Gaudet shooting because they had feared that the Rice and Gaudet shootings might be “signature crimes,” given the similarities between the two incidents. Id. at 114; see also id. at 106. 2
Deputy Anderson swore out two affidavits, one in support of a search warrant for George’s residence and one in support of a search warrant for George’s truck. The affidavit supporting the search warrant for the residence recited as follows:
George was found and located in the immediate vicinity at or near the time ... Dallas P. Rice was shot and is a suspect in the shooting. The affiant has also personally observed rifles in said residence, and the said Cyrus J. George has been observed test firing high powered rifles within close proximity to the above described residence.
Id. at 200. This affidavit sought authorization to search for “any and all high powered rifles, cartridges, bullets, components, cartridge cases [or] boxes, expended bullets, other firearms, ammunition, reloading components ■ and equipment, hacksaws, clothing and footwear.” Id.
*1116 The affidavit submitted in support of the search warrant for George’s truck sought authorization to search for the same items, plus “tires located on the ... truck.” This affidavit read in relevant part:
George was found in the immediate area at or near the time of [the Rice] shooting in the above mentioned vehicle; affiant has knowledge that the said Cyrus J. George has carried the above items in said truck; the affiant is of the belief that the above vehicle was used in the commission of said offense and was being operated by the said Cyrus J. George at the time of said offense.
Id. at 195.
Deputy Anderson also swore out a complaint in support of a warrant for George’s arrest. See id. at 125-26. Although this complaint is not in the record, the government represents that the complaint stated as follows:
Cyrus J. George was found in the immediate vicinity of the location where ... Dallas P. Rice was shot at the time of the shooting; ... pieces of a rifle belonging to Cyrus J. George were found in the immediate area of said shooting, and ... no other person or person(s) were found in [the] area.
Appellant’s Br. at 10 n. 8.
A county magistrate issued the three requested warrants on February 5, 1987, and George was arrested that day while in his truck. His truck was impounded, see App. at 159, and tires and three hacksaw blades, among other items, were seized from the vehicle, see id. at 193. Three pairs of boots and various other items were seized from George’s residence. See id. at 198. Only the tires, hacksaw blades, and boots seized pursuant to the warrants are at issue in this appeal.
On April 16,1990, George was indicted in the United States District Court for the Northern District of West Virginia on a variety of racketeering counts, including two counts of conspiring to commit murder in aid of racketeering, one count of maiming in aid of racketeering, and one count of attempted murder in aid of racketeering. See generally id. at 8-70. George filed two suppression motions relating to the evidence seized pursuant to the search warrants for the truck and the residence. See id. at 71-81.' After an evidentiary hearing on these motions, a federal magistrate issued proposed findings of fact and recommended that the court grant the motions. See id. at 133-45.
The federal magistrate concluded that both warrants were invalid because the affidavits presented to the county magistrate were “too scanty and too far removed in time to support a finding of ‘present’ probable cause.”
Id.
at 139. The magistrate rejected the argument of the United States that the county officers had reasonably relied in good faith upon the warrants and that the evidence was therefore admissible on the authority of
United States v. Leon,
The United States filed objections to the magistrate’s proposed findings and recommendations. See id. at 146-60. The government objected to the magistrate’s finding that the warrants were not supported by probable cause and that the challenged evidence was not admissible under the good faith exception to the exclusionary rule. It also raised for the first time two additional arguments in opposition to the suppression motions. First, the government argued that George “had no reasonable expectation of privacy” in his *1117 truck tires and that he thus was not entitled to suppression of the tire treads. Id. at 157. Second, the government argued that the items on and in George’s truck— specifically the tires and hacksaw blades— inevitably would have been discovered and therefore were admissible under the inevitable discovery exception to the exclusionary rule. See id. at 158-59. • The district court adopted the magistrate’s proposed findings and recommendations “in totality,” refusing to consider the government’s privacy and inevitable discovery arguments because the government had not raised these arguments before the magistrate. Id. at 167. The court subsequently denied the government’s motion to reconsider, reemphasizing its unwillingness to entertain the “untimely” privacy and inevitable discovery arguments. See id. at 177-81.
The United States appeals the district court’s grant of Géorge’s suppression motion. See 18 U.S.C. § 3731.
II.
The United States first contends that the district court violated the Federal Magistrates Act, 28 U.S.C. §§ 631-639, by refusing to consider the government’s arguments that the tires and the hacksaw blades were admissible because George had no cognizable privacy interest in his tires and because the hacksaw blades inevitably would have been discovered. 3 As noted, although the government presented these arguments in its objections to the magistrate’s findings and recommendations, the district court refused to consider either argument because the government had not presented them before the magistrate:
The Government’s objections concerning “expectation of privacy” and “inevitable discovery” raise issues of law and fact which were not presented in its written response to the motions to suppress or at the suppression hearing. The Court has previously advised the Government that attempts to introduce additional evidence or raise new arguments subsequent to an adverse ruling by the Magistrate will not be permitted by the Court_
App. at 167.
The Federal Magistrates Act permits a district court judge to refer a pretrial suppression motion to a magistrate for the conduct of hearings, including evidentiary hearings.
See
28 U.S.C. § 636(b)(1)(B).
4
Upon the completion of hearings, the magistrate submits proposed findings of fact and recommendations to the court, which “shall make a de novo determination of those portions of the report or specified proposed findings or recommendations to which objection is made.”
Id.
§ 636(b)(1);
see Wimmer v. Cook,
We believe that as part of its obligation to determine
de novo
any issue to which proper objection is made, a district court is required to consider all arguments directed to that issue, regardless of whether they were raised before the magistrate.
6
By definition,
de novo
review entails consideration of an issue as if it had not been decided previously. It follows, therefore, that the party entitled to
de novo
review must be permitted to raise before the court any argument as to that issue that it could have raised before the magistrate. The district court cannot artificially limit the scope of its review by resort to ordinary prudential rules, such as waiver, provided that proper objection to the magistrate’s proposed finding or conclusion has been made and the appellant’s right to
de novo
review by the district court thereby established.
7
Not only is this so as a matter of statutory construction; any other conclusion would render the district court’s ultimate decision at least vulnerable to constitutional challenge.
See United States v. Raddatz,
Accordingly, it was incumbent upon the district court to consider the arguments by the United States that George had no cognizable privacy interest in the tires of his truck and that the hacksaw blades inevitably would have been discovered.
See Shami,
III.
The United States argues that the “district court plainly erred in suppressing the truck tires” because George does not *1119 have an objectively reasonable expectation of privacy in tires on a truck that he drives and parks in public places. Appellant’s Br. at 32. We agree.
The Fourth Amendment protects only those “expectations] of privacy ... that society accepts as objectively reasonable,”
California v. Greenwood,
A majority of the Supreme Court has never held that there is no legitimate expectation of privacy in the exterior of a vehicle. A plurality of the Court in
Card-well v. Lewis,
There is thus little question in the aftermath of Cardwell and Class that one does not have a reasonable expectation of privacy in the visible exterior parts of an automobile that travels the public roads and highways. If, as the Court held in Class, there is no privacy interest in the interior of an automobile visible from the outside, 10 a fortiori, as the Cardwell plurality recognized and the Class majority assumed, there can be no privacy interest in the visible exterior portions of an automobile. 11
George was arrested while in his truck. As in
Cardwell,
George’s truck “was seized from a public place where access was not meaningfully restricted.”
Card-well,
IV.
The United States next argues in reliance on
Nix v. Williams,
We agree for the reasons stated by the government that the inevitable discovery exception to the exclusionary rule is theoretically available to support admission of the hacksaw blades. County police had two lawful bases for arresting George. The police had secured a warrant for George’s arrest, the validity of which George does not challenge. In addition, as George himself appears to concede, the police had probable cause to arrest George within days after the Rice shooting, if not sooner.
See
Appellee’s Br. at 19. The police could have arrested George in a public place based on this probable cause alone.
See United States v. Watson,
Once the truck was lawfully in police custody, there were two ways in which the police lawfully could have found the hacksaw blades. First, they could have executed the search warrant for the truck, which they in fact did. Second, even in the absence of the search warrant, the police could have conducted a routine inventory search, during which the hacksaw blades might have been discovered. Thus, even if the search warrant was defective and
Leon’s
good faith exception inapplicable,
12
the inevitable discovery doctrine would permit the introduction of the hacksaw blades into evidence if the police would have found the blades pursuant to an inventory search of the lawfully impounded vehicle.
See Nix,
Although we accept the theory of the government’s inevitable discovery argument, we are unprepared to reverse outright the portion of the district court’s suppression order relating to the hacksaw blades because, as the United States con
*1122
cedes,
see
Appellant’s Reply Br. at 8, there has been no opportunity to establish that the blades inevitably would have been discovered during the course of executing the county’s standard inventory search. We therefore vacate the portion of the district court’s suppression order relating to the hacksaw blades and remand the case for factfinding solely on the question of whether the hacksaw blades that were found in George’s truck pursuant to the search warrant would have been discovered in any event pursuant to a standard inventory search by Upshur County police.
13
Because the hacksaw blades were located in a tool box inside the truck, the government must prove that under standard inventory procedures, the police would have opened the tool box in which the blades were in fact found.
See Florida v. Wells,
V.
We address, finally, whether suppression of the boots recovered upon execution of the search warrant for George’s residence is required.
After concluding that the residential warrant was not supported by probable cause,
see
App. at 139, the magistrate rejected the United States’ argument that evidence recovered on the authority of this warrant should nonetheless be admitted under the good faith exception to the exclusionary rule recognized in
United States v. Leon,
*1123 Upon reviewing the United States’ objection to this portion of the magistrate’s report, the district court agreed with the magistrate that “the primary purpose” for obtaining the residence warrant “was to seek incriminating evidence in the ... Gau-det investigation” and that under such circumstances, “the good-faith exception to the exclusionary rule is not available.” Id. at 167. 15
We believe that the magistrate and the district court erred in refusing to apply the good faith exception of
Leon
on the basis of their asserted belief that the police sought the residence warrant to acquire evidence in the Gaudet case rather than in the Rice case. Apart from the fact that the belief of the magistrate and the district court as to the motivations of the police who sought the warrant lacked reasonable foundation,
16
their inquiry into the subjective motivations of the officers was irrelevant to the applicability of
Leon.
The only relevant inquiry under
Leon
is whether it was “objectively reasonable” for the officers who executed the subsequently invalidated warrant to have relied upon the warrant.
Leon,
When the inquiry is properly focused on the objective reasonableness of the officers’ actions, it is evident that the officers did reasonably believe that their conduct was fully consistent with the Fourth Amendment. The police officers consulted with the county prosecutor as to whether to apply for the search warrant. After receiving his approval, they sought and received the warrant from a duly authorized judicial officer. The warrant was facially valid, and the magistrate found as a factual matter that the affidavit contained no false statement.
See
App. at 141-42;
cf. Sheppard,
We conclude as a matter of law, therefore, that the county police were objectively reasonable in their reliance on the search warrant pursuant to which they searched George’s residence. There is no basis for believing that “a reasonably well trained officer would have known that the search was illegal despite the magistrate’s authorization.”
Leon,
CONCLUSION
For the reasons set forth above, the district court’s order is reversed insofar as it directed suppression of the truck tires and boots seized from George’s truck and residence, respectively, and it is vacated insofar as it ordered suppression of the hacksaw blades. • The case is hereby remanded for further proceedings not inconsistent with this opinion.
*1125 REVERSED IN PART, VACATED IN PART, AND REMANDED
Notes
. According to an FBI report, bullets recovered from the shooting scene were consistent with those fired from a .30/30 Winchester rifle. See id. at 268. The report apparently also concluded that the gun parts recovered from the river had been placed in the river at approximately the time of the Rice shooting. See id. at 267.
. Both incidents occurred at dusk, and each time, a gunman fired a rifle from a position concealed by heavy vegetation. See id. at 108-10. In each instance, the gunman parked his vehicle a quarter mile away and then walked to the “blind” from which shots were taken. See id. at 108-09.
. The tires and the hacksaw blades were recovered during the execution of the search warrant issued for George’s truck. The district court found that the affidavit and complaint in support of this warrant failed to establish probable cause, see App. at 138-39, 164-66, and the government does not contest this finding. The district court also declined to apply Leon’s good faith exception so as to permit admission of the evidence recovered pursuant to this warrant. See id. at 140-41, 166. In light of our disposition of the government’s appeal with respect to the tires and the hacksaw blades, see parts II-IV., infra, we need not and do not address these aspects of the district court’s order.
. A “judge may ... designate a magistrate to conduct hearings, including evidentiary hearings, and to submit to a judge of the court proposed findings of fact and recommendations for the disposition, by a judge of the court,” of a motion to suppress evidence in a criminal case. Id. '
.The Federal Magistrates Act as originally enacted did not specify by terms that the district court must review
de novo
the magistrate’s findings and recommendations.
See generally Wimmer,
.A motion to suppress decided by a magistrate is not one of the pretrial matters that may be reviewed by the district court merely for clear error or plain error.
See id.
§ 636(b)(1)(A). Congress’ failure to prescribe a "clearly erroneous” standard of review for suppression motions reinforces the need for the district court to conduct plenary,
de novo
review of such matters.
Cf. Thomas v. Am,
.A party waives the right to appellate review of a magistrate’s decision if it fails to object to the proposed decision before the district court.
See United States v. Schronce, IT!
F.2d 91, 94 (4th Cir.),
cert, denied,
. Justice Powell did not reach the expectation.of privacy question in
Cardwell.
He would have held that the Fourth Amendment claim was not reviewable on federal collateral review because the state prisoner had a full and fair opportunity to litigate that claim in state court.
See id.
at 596,
. Justice Powell was a member of the five-justice majority in
Class
that endorsed the plurality holding in
Cardwell
that there is no reasonable expectation of privacy in the exterior of an automobile.
See Class,
. Numerous decisions have affirmed this principle.
See, e.g., Brumfield
v.
Jones,
.
See, e.g., United States v. Muniz-Melchor,
. Because we instruct the district court on remand to conduct further proceedings on. the inevitability of the discovery of the hacksaw blades, we do not address the government’s alternative argument that the district court erred in declining to admit the blades under Leon. See also note 3 supra.
. The United States represents that "Upshur County does have established written procedures that require an inventory of items in a seized vehicle.” Appellant’s Reply Br. at 7. The district court on remand should take judicial notice of these published policies and procedures.
See
Fed.R.Evid. 201;
Newcomb v. Brennan,
. The magistrate's conclusion was also based on his assumption that "the authorities had recovered most of what they believed to be the rifle used in 5285 28 7 [the Rice] shooting.” Id.; see abo id. at 166 n. 6. Even if it were true that the authorities had found most of the rifle, it would not follow that they would have had no reason to search George’s residence. Such a search could have uncovered a myriad of evidence. For instance, the police could have found additional rifle parts or .30/30 shells, which would have further incriminated George in the Rice shooting.
. The district court also criticized the affidavit supporting the search warrant for the residence because "the affiant statefd] that he ha[d] personally observed rifles in the residence” but later "testified that he had seen
one
rifle in the residence five years earlier.”
Id.
at 166. Although the court agreed with the magistrate that the affidavit included no "knowing and intentional misstatement[s]," the district court suggested that the affiant’s reference to rifles evidenced “at least ... a reckless disregard for the whole truth which misled the issuing judicial officer.”
Id.
Even if we assume that the district court’s suggestion that the affiant had recklessly disregarded the truth was not clearly erroneous, it is apparent that this misstatement was immaterial.
Franks
v.
Delaware,
. The magistrate and district court assumed that if the police were seeking evidence of the Gaudet shooting, they necessarily were not seeking evidence of the Rice shooting. In effect, the magistrate and district court ignored the fact that county police had reason to believe that George may have committed both crimes and thus that the police expected to find evidence in George’s residence that would be relevant to both crimes.
. The Court’s reliance in
Leon
upon an objective standard and its rejection of inquiries into the subjective states of mind of the individual officers is consistent with the Supreme Court’s general Fourth Amendment jurisprudence of reliance upon “objective standards of conduct, rather than standards that depend upon the subjective state of mind of the officer."
Horton v. California,
