OPINION
¶ 1 In this special action, the Arizona Independent Redistricting Commission (“IRC”) challenges the trial court’s order granting a motion by the Arizona Minority Coalition for Fair Redistricting (“Coalition”) to compel the IRC to produce documents exchanged between the IRC, its consultants, and expert witnesses. The IRC claims that the requested documents are protected from disclosure by legislative, deliberative process, attorney-client, and work-product privileges. The trial court found that none of these privileges applied to immunize the documents from disclosure. We decide that communications between the IRC and its consultants are subject to the protection afforded by the legislative privilege. While we do not decide the applicability of the deliberative process privilege, the attorney-client and work-product privileges are inapplicable. Additionally, by designating consulting experts as testifying experts, the IRC waived any legislative privilege attaching to communications with those experts, or any materials reviewed by them, that relate to the subject of the experts’ testimony.
¶ 2 For the reasons that follow, we accept jurisdiction and grant relief to the IRC in the manner described hereafter. See infra ¶ 51.
BACKGROUND
¶ 3 Since the grant of statehood, Arizona voters living in artificially drawn districts have selected residents from those districts to serve in Congress and the state legislature. Ariz. Const, art. IV, Pt. 2, § 1(1), (2) (historical notes to 2000 amendment). Historically, and in recognition of population changes, our legislature undertook the task of redrawing these districts from time to time.
Id.
Because of past violations of the Voting Rights Act, 42 U.S.C. § 1973c (1994), Section 5 of the Act requires Arizona to submit such redistrieting plans for preelearance to either the United States Department of Justice (“DOJ”) or the District Court for the District of Columbia.
Navajo Nation v. Arizona Indep. Redistricting Comm’n,
¶4 In November 2000, Arizona voters passed Proposition 106, which amended the constitution by creating the IRC and assigning to it the redistricting task. Ariz. Const, art. IV, Pt. 2, § 1(3) (historical notes to 2000 amendment). The IRC is thus a constitutional body that consists of five appointed volunteers who serve concurrent, ten-year terms. Ariz. Const, art. IV, Pt. 2, §§ 1(3), (23). The IRC members are not required to have any expertise in the redistricting process. Ariz. Const, art. IV, Pt. 2, § 1(3). However, the constitution authorizes the IRC to hire staff, consultants, and attorneys to assist it. Ariz. Const, art. IV, Pt. 2, § 1(19).
¶ 5 The IRC must ensure that configuration of the districts complies with the United States Constitution and the Voting Rights Act. Ariz. Const, art. IV, Pt. 2, § 1(14)(A). Furthermore, “[t]he IRC must attempt to create competitive districts to the extent practicable” when doing so would not create a significant detriment to other factors, such as compactness, contiguity, and communities of interest.
Navajo Nation,
¶ 6 The 2000 decennial census revealed substantial population growth in Arizona and shifts within pre-existing districts.
Navajo Nation,
¶ 7 Pending preclearance from the DOJ, the Coalition and other parties filed a complaint against the IRC in March 2002, alleging that the IRC violated the Arizona Constitution by failing to make the legislative districts sufficiently competitive. Id. at 1002. When the Coalition sought to depose the IRC members and NDC consultants and obtain responses to written discoveiy requests, the IRC moved the court for an order precluding discovery concerning “legislative acts.” On April 15, the court granted the motion as to the commissioners but ruled that the Coalition could depose the consultants. On April 30, the court clarified that it “does not view the consultants ... as legislative aides entitled to a deliberative process privilege.” Accordingly, the Coalition deposed NDC consultants Douglas Johnson, and Drs. Alan Heslop, Michael McDonald, and Lisa Handley. The IRC later designated these consultants as expert witnesses for purposes of testifying at the trial in this case.
¶ 8 In September 2002, in light of looming primary and general elections, the IRC obtained federal distinct court approval for an interim redistricting plan for use in these elections.
Navajo Nation,
¶ 9 The Coalition submitted a document request to the IRC seeking “all documents, communications, etc., that have been withheld for privilege,” including “all email communications pertaining to redistricting contained on Doug Johnson’s computer in California.” On February 24, 2003, the IRC produced two binders of documents but withheld documents exchanged with NDC and its counsel on the basis of multiple privileges. According to the IRC, most of these documents are paper print-outs of electronic mail.
¶ 10 On March 4, the Coalition filed a motion to compel production of all documents that were created by, or provided to, the IRC’s testifying expert witnesses, as well as all communications with the IRC’s vendors, including NDC. The trial court granted the Coalition’s motion to compel on March 21, ruling that while the IRC has a privilege for its deliberative process, that privilege does not extend to communications with its consultants. The court additionally found that the requested documents are not protected by the attorney-client or work-product privileges, and that all communications between IRC’s expert witnesses and counsel are discoverable. This special action followed, and we entered an order staying the trial court’s discovery order pending our resolution of the issues. On May 30, 2003, the IRC removed the case to the Arizona District Court. By order dated September 5, 2003, that court remanded the matter to the superior court, thereby revesting jurisdiction in this court.
SPECIAL ACTION JURISDICTION
¶ 11 The exercise of special action jurisdiction is appropriate to review an order compelling discovery over the objection of a party asserting privileges because that party has no equally plain, speedy, or adequate remedy by appeal.
Twin City Fire Ins. Co. v. Burke,
*136
¶ 12 Nevertheless, the Coalition urges us to decline jurisdiction under the doctrine of laches because the IRC unreasonably delayed seeking relief by not petitioning for review of the court’s April 30, 2002, ruling that the IRC’s communications exchanged with the NDC consultants are not shielded by a deliberative process privilege. We agree that the IRC could have obtained judicial resolution of many of the issues now before us by seeking review of this earlier order. We are additionally concerned that these proceedings might delay the trial in this case. Notwithstanding, courts should hesitate to enforce a claim of laches against a public body that is asserting privileges designed to serve the public interest.
See Maricopa County v. Cities and Towns of Avondale,
DISCUSSION
¶ 13 The IRC argues that the trial court erred by compelling production of documents exchanged between the IRC and NDC because those documents are exempt from disclosure under the legislative, deliberative process, attorney-client, and work-product privileges. The IRC additionally contends that it did not waive any of these privileges by designating NDC consultants as testifying expert witnesses.
¶ 14 The existence of an evidentiary privilege is a question of law, which we review de novo.
Twin City Fire Ins. Co.,
A. Legislative Privilege
1. Overview
¶ 15 The so-called “legislative privilege” asserted by the IRC stems from the doctrine of legislative immunity, which in turn springs from common law and is embodied in the Speech or Debate Clause of the United States Constitution
1
and the principles underlying our government’s separation of powers.
See Bogan v. Scott-Harris,
*137
¶ 16 The United States Supreme Court has held that common law legislative immunity similar to that embodied in the Speech or Debate Clause exists for state legislators acting in a legislative capacity.
Bogan,
V17 The legislative immunity doctrine also functions as a testimonial and evidentiary privilege.
Marylanders For Fair Representation, Inc., v. Schaefer,
¶ 18 This legislative privilege does not extend to cloak “all things in any way related to the legislative process.”
Steiger,
¶ 19 The IRC argues that the trial court erred by compelling production of documents exchanged between the IRC and NDC because such communications are protected by the legislative privilege. According to the IRC, because NDC assisted the IRC in performing legislative tasks, the legislative privilege extends to protect them communications and acts undertaken during the redistricting process. The Coalition does not contest for purposes of the discovery dispute that the IRC is entitled to assert the legislative privi
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lege, but contends that the privilege does not extend to NDC as an independent contractor. The Coalition alternatively asserts that if the privilege extends to NDC, the privilege does not protect against the disclosure of documents. Before deciding the applicability of the legislative privilege to NDC and its scope, however, we first address the City of Flagstaff s
5
contention that the IRC commissioners do not hold a legislative privilege, and such a privilege therefore cannot extend to NDC.
See Gravel,
2. Applicability to the IRC
¶ 20 The City first asserts that because the IRC commissioners are appointed rather than elected, they are not entitled to assert the legislative privilege. We reject this argument. The Supreme Court has developed a “functional” approach to determine who may assert the legislative privilege, which is not dependent on the manner of selection for office.
Lake Country Estates, Inc., v. Tahoe Reg’l Planning Agency,
¶21 The City also argues that the IRC does not perform any legislative acts and consequently is not entitled to assert the legislative privilege. Specifically, the City contends that because our constitution expressly directs the IRC in the redistricting process, the IRC performs an administrative function rather than a legislative function by implementing this directive.
Bryan,
¶ 22 The IRC’s redistricting acts are legislative in nature. Although the constitution provides a framework for the redistricting task, along with multiple goals for establishing districts, the commissioners exercise discretionary, policymaking decisions within that framework to balance these goals and arrive at a final redistricting plan. See, e.g., Ariz. Const, art. IV, Pt. 2, § 1(14)(F) (“To the extent practicable, competitive districts should be favored where to do so would create no significant detriment to the other goals.”). Thus, the IRC does not, as the City suggests, merely implement an established redistricting policy.
¶ 23 Additionally, the redistricting plan has the force of law, with prospective application. *139 Ariz. Const, art. IV, Pt. 2, § 1(17) (“[t]he provisions regarding this section are self-executing”). 7 Undeniably, enacting laws is an act traditionally performed by the legislature. Indeed, prior to the 2000 amendment to our constitution, the legislature undertook the redistricting task. See supra ¶3. For these reasons, we conclude that the IRC performs legislative acts when formulating a redistricting plan. 8
¶ 24 In conclusion, the IRC commissioners, who are constitutional officers, are cloaked with legislative privilege for actions that are “an integral part of the deliberative and communicative processes” utilized in developing and finalizing a redistricting plan, and “when necessary to prevent indirect impairment of such deliberations.”
Gravel,
3. Applicability to consultants
¶25 The IRC argues that the trial court erred by refusing to extend the legislative privilege to shield communications between the IRC and NDC consultants. The Coalition responds that the privilege cannot shield independent consultants because they are not “direct participants] in the legislative process,” but are, rather, mere providers of information and services. In an
amicus curiae
brief, members of the Arizona Legislature urge us to extend the privilege to outside consultants “as long as some authority has been delegated by the Legislature or a member for the [consultant] aide to engage in legislative acts.” Our resolution of this issue is guided by the Court’s decision in
Gravel.
¶ 26 The dispute in
Gravel
arose from Senator Mike Gravel’s acts of reading aloud from the so-called “Pentagon Papers”
9
during a hearing of a Senate subcommittee chaired by the senator, and then placing that document in the public record.
¶ 27 The Court held that although the privilege was personal to Senator Gravel, and invocable only by him or an aide on his behalf, the privilege extended to Dr. Rodberg insofar as his conduct would be protected legislative acts if performed by the senator.
Id.
at 616, 618, 621-22,
¶ 28 The Court’s holding in
Gravel
turned on the function fulfilled by Dr. Rodberg rather than his job title.
Id.
at 621-23,
¶ 29 Moreover, as the members of the Arizona Legislature point out, the modem, part-time legislature, in light of budgetary constraints, contracts with expert consultants on a variety of subjects rather than retaining staff with such expertise. Thus, applying the cramped interpretation of the legislative privilege urged by the Coalition would constrain legislators from freely engaging in legislative acts without the threat of executive or judicial oversight; the core concern of legislative privilege.
See Gravel,
¶ 30 For all these reasons, we decide that a legislator may invoke the legislative privilege to shield from inquiry the acts of independent contractors retained by that legislator that would be privileged legislative conduct if personally performed by the legislator. The privilege is held solely by the legislator and may only be invoked by the legislator or by an aide on his or her behalf.
Id.
at 621-22,
4. Applicability to documents
¶ 31 The Coalition alternatively argues that even assuming the applicability of the legislative privilege to NDC, the privilege is only testimonial and evidentiary in nature and does not shield documents from disclosure. The IRC maintains that the privilege would be illusory if communications otherwise protected from inquiry were discoverable if in written form. Neither the Supreme Court nor any Arizona court has addressed this issue, and other courts have reached differing resolutions of the issue. 10
¶32 We are persuaded the legislative privilege protects against disclosure of documents in appropriate circumstances. The Supreme Court has held that the privilege applies to forbid questioning of witnesses concerning a legislator’s conduct in performing legislative acts and communications between a legislator and his or her aides during their term of employment and related to any legislative act.
Gravel,
B. Deliberative Process Privilege
¶33 The IRC also argues that the trial court erred by compelling disclosure of the contested documents because they are protected by the “deliberative process privilege.” The deliberative process privilege is a federal common law privilege preserved in “Exemption 5” of the Freedom of Information Act, 5 U.S.C. § 552(b)(5) (1996) (“FOIA”), which shields from mandatory disclosure “inter-agency or intra-agency memorandums or letters which would not be available by law to a party other than an agency in litigation with the agency.”
Paisley v. CIA
¶ 34 The Coalition contends that the deliberative process privilege does not cloak any IRC documents because Arizona’s public records law, A.R.S. § 39-121 to -161 (2001 & Supp 2002), does not contain a provision equivalent to Exemption 5 of FOIA, and Arizona courts have not acknowledged a common law privilege.
See Star Pub’g Co. v. Pima County Attorney’s Office,
C. Common Interest Doctrine
¶ 35 The IRC next contends that the trial court erred by compelling disclosure of documents protected by the attorney-client and/or work product privileges, as extended through the “common interest doctrine.”
11
The Coalition responds that the communications between the IRC and NDC did not concern a common interest, and the doctrine therefore does not apply. Because Arizona courts have not addressed the common interest doctrine, we look to the Restatement (Third) of Law Governing Lawyers (“Restatement”) (2000) for guidance.
See Burns v. Davis,
¶ 36 Restatement § 76(1) describes the common interest doctrine as follows:
*142 If two or more clients with a common interest in a litigated or nonlitigated matter are represented by separate lawyers and they agree to exchange information concerning the matter, a communication of any such client that otherwise qualifies as privileged [as attorney-client communications] that relates to the matter is privileged as against third persons. Any such client may invoke the privilege, unless it has been waived by the client who made the communication.
The doctrine does not create a privilege, but is an exception to the rule that communications between a person and a lawyer representing another person are not privileged. Restatement § 76, Reporters Note cmt. c.
¶37 Exchanged communications subject to the common interest doctrine must themselves be privileged as well as related to the parties’ common interest, “which may be either legal, factual, or strategic in character.” Restatement § 76 cmt. e, Reporters Note cmt. d. Such communications may be made between any member of a “client set” 12 and a member of a similar client set. Restatement § 76 cmt. d. However, communications solely among clients do not fall within the common interest doctrine. Id. Finally, the doctrine allows “persons similarly aligned on a matter of common interest” to exchange privileged work product without waiving that privilege. Restatement § 91 cmt. b.
¶ 38 The IRC asserts that the common interest doctrine shields from disclosure communications between it and NDC because the parties had a common legal interest in a non-litigated matter — the redistrieting of Arizona in compliance with applicable laws — and each party had legal representation. Following our charge to construe privileges narrowly,
Nixon,
¶ 39 The purpose of the common interest doctrine is to permit persons with common interests to share privileged attorney-client and work-product communications in order to coordinate their respective positions without destroying the privilege. Restatement § 76 cmt. b, § 91 cmt. b. Because the attorney-client privilege only applies to confidential communications made for the purpose of obtaining or providing legal assistance for the client, A.R.S. § 12-2234(B) (2003), it follows that the common interest doctrine protects only those communications made to facilitate the rendition of legal services to
each
of the clients involved in the conference.
See In re Santa Fe Int’l Corp.,
¶40 The IRC has failed to demonstrate that any communications or work product exchanged between it and NDC furthered legal interests of both parties. Although the IRC and NDC may share a common goal of drafting a legally viable redistricting plan, they do not share a common
legal
interest, as the IRC contends. The IRC is constitutionally charged with redistricting and it alone is
*143
accountable to the public in performing that task. By contrast, NDC is not legally responsible for redistricting and cannot be held liable to the public for any errors in that process. Rather, NDC has only a contractual obligation to provide specified information and services to the IRC to assist in the redistricting process. Thus, even though the IRC and NDC may share a desire to craft a redistricting plan that complies with all applicable laws, they do not possess a common legal interest.
In re Grand Jury Subpoena Duces Tecum,
¶41 Therefore, the communications and documents exchanged between the IRC and NDC are not protected by the attorney-client or work-product privileges, as extended by the common interest doctrine.
D. Waiver
¶ 42 The IRC finally challenges the trial court’s ruling that the IRC waived any privileges applicable to communications between its attorneys and the NDC consultants by designating these consultants as testifying expert witnesses. Because the legislative privilege is the only privilege that potentially shields some or all of these communications, given the narrower shield, if any, afforded by the deliberative process privilege, see supra ¶¶30, 32, 34, we confine our discussion to that privilege.
¶ 43 Both parties acknowledge that resolution of this issue turns on the breadth of this court’s decision in
Emergency Care Dynamics, Ltd. v. Superior Court,
¶ 44 Second, Arizona Rules of Civil Procedure (“ARCP”) 26(b)(4), governing discovery of experts, supported the court’s decision.
Id.
at 36,
*144
¶ 45 Third, and finally, the court explained that a “bright-line” rule for discovery aimed at experts employed jointly as consultants and testifying experts was preferable to engaging in expensive and time-consuming discovery disputes to determine which role the expert was playing when he or she reviewed a particular document.
Id.
at 37,
¶ 46 The IRC contends that Emergency Care applies only to waiver of the work-product privilege, and has no application to the legislative privilege. The Coalition responds that the designation of a consultant as a testifying expert waives any legislative privilege attaching to materials considered by that expert in forming his or her opinions. We agree with the Coalition.
¶ 47 Although
Emergency Care
dealt only with waiver of the work-product privilege, the sole issue before it, the court’s reasoning is equally applicable to waiver of the legislative privilege.
¶ 48 We also disagree with the IRC that the reasoning in
Emergency Care
is inapplicable because the legislative privilege has constitutional origins. The holder of a legislative privilege can waive the privilege on his or her own behalf or for aides.
Gravel,
¶ 49 Finally, like the attorneys in
Emergency Care,
the IRC and its attorneys exclusively control the selection of its testifying experts. Thus, the IRC can avoid waiving any legislative privilege by simply selecting testifying experts who did not also serve as pre-litigation consultants. Although such a practice may be expensive, the costs “are likely cumulatively to be lesser than the systemic costs of innumerable discovery battles over expert witness files.”
Emergency Care,
¶ 50 In summary, we hold that by designating consulting experts as testifying experts, the IRC waived any legislative privilege (1) attaching to communications with *145 those experts, or any materials reviewed by them, and (2) relating to the subject of the expert’s testimony. 14 Any legislative privilege shielding communications with such experts, or any materials reviewed by them, that do not relate to the particular subject of the expert’s testimony, remain privileged.
RELIEF GRANTED
¶ 51 We vacate that portion of the trial court’s order dated March 21, 2003 compelling the IRC to produce documents exchanged with NDC consultants that are both protected by the legislative privilege and have not been waived by the IRC’s designation of these consultants as testifying experts. We direct the IRC to immediately identify those documents listed on its privilege log that fit this criteria. The IRC shall immediately produce to the Coalition all remaining documents listed in the privilege log. Thereafter, and without undue delay, the IRC shall submit any documents it deems privileged and not waived to the trial court for an in camera inspection. The court shall then decide whether these documents are shielded by the legislative privilege.
¶52 The IRC asks us to award it attorneys’ fees pursuant to A.R.S. §§ 12-349(A), - 350 (2003). The Coalition seeks a fee award pursuant to ARCP 37(a)(4) and Arizona Rule of Procedure for Special Action § 4(g). In our discretion, we deny both requests.
¶ 53 Finally, upon the filing of this opinion, we vacate our prior stay order.
Notes
. The Speech or Debate Clause of the United States Constitution, art. I, § 6, cl. 1, provides, in pertinent part, as follows: "[F]or any Speech or Debate in either House, [senators and representatives] shall not be questioned in any other Place.”
. A thorough history of the origins of legislative immunity is set forth in
Holmes v. Farmer,
. The Speech or Debate Clause in the Arizona Constitution, art. IV, Pt. 2, § 7, provides: "No member of the Legislature shall be liable in any civil or criminal prosecution for words spoken in debate.”
. As the Coalition noted at oral argument before this court, Arizona’s Speech or Debate Clause differs from its federal counterpart by not explicitly prohibiting the questioning of legislators. This distinction is not significant. By the time the Framers convened the Arizona Constitutional Convention in 1910, the Supreme Court had liberally construed the federal Speech or Debate Clause to protect against inquiry about the exercise of legislative functions.
Kilbourn v. Thompson,
. The City o£ Flagstaff is a plaintiff in this case and has intervened in the special action.
. Our supreme court's decision in
Grimm v. Arizona Bd. of Pardons and Paroles,
. A "self-executing” constitutional provision is immediately effective without the necessity of ancillary legislation.
See Calmat of Arizona v. State ex rel. Miller,
. Other courts have reached similar decisions.
See Marylanders For Fair Representation,
. The Pentagon Papers was a classified Defense Department study formally titled "History of the United States Decision-Making Process on Viet Nam Policy.”
Gravel,
. For cases supporting the Coalition's position,
see In re Grand Jury (Granite Purchases for State Capital-Grand Jury Subpoena No. 86-1),
For cases supporting the IRC’s position,
see Brown & Williamson Tobacco Corp., v. Williams,
. According to the IRC, it and NDC entered a "Joint Defense Agreement” at the commencement of their relationship in order to memorialize their intent to preserve applicable privileges when communicating about common legal interests. The IRC admits that the Agreement itself cannot create a privilege, and we agree.
See Aetna Cas. & Sur. Co. v. Certain Underwriters at Lloyd's London,
. A "client set” consists of a client (including a prospective client), the client's agent for communication, the client's lawyer, and the lawyer’s agent. Restatement §§ 70, 76 cmt. d.
.
At the time the court decided
Emergency Care,
Rule 26(b)(4)(A)(ii) authorized the court, upon
*144
motion, to order discovery against experts by means other than interrogatories "subject to such restrictions as to scope ... as the court may deem appropriate.”
Emergency Care,
. No one contends that the IRC did not act on behalf of the individual commissioners when it designated the consulting experts as testifying experts. Thus, we do not address whether the IRC, as a body, could waive any legislative privilege held by a commissioner.
