The opinion of the court was delivered by: Reggie B. Walton United States District Judge
The Muwekma Ohlone Tribe ("Muwekma," "the Tribe," or "the plaintiff")*fn2 brings this action under the United States Constitution and the Administrative Procedure Act ("APA"), 5 U.S.C. §§ 554, 701-706 (2000), seeking review of the "Final Determination Against Federal Acknowledgment of the Muwekma Ohlone Tribe" ("Final Determination"), 67 Fed. Reg. 58,631 (2002), issued by the Department of the Interior ("DOI" or "the Department"),*fn3 which declined to grant federal recognition to Muwekma as a Native American tribe pursuant to the acknowledgment criteria of 25 C.F.R. § 83 (2006) ("Part 83"). Complaint ("Compl.") ¶ 1. Specifically, Muwekma contends, inter alia, that the Department violated the Equal Protection Clause and the APA by requiring it to undergo the Part 83 acknowledgment procedures while allowing similarly situated tribal petitioners to bypass these procedures altogether. Compl. ¶¶ 37-39; Points and Authorities in Support of Plaintiff's Motion for Summary Judgment ("Pl.'s Mem.") at 22-30. Currently before the Court are the parties' cross-motions for summary judgment.*fn4 For the reasons set forth below, the Court denies both parties' motions without prejudice and directs the Department to supplement the administrative record.
The following facts are not in dispute. Muwekma is a group of American Indians indigenous to the San Francisco Bay area, the members of which are direct descendants of the historical Mission San Jose Tribe, also known as the Pleasanton or Verona Band of Alameda County ("the Verona Band"). Pl.'s Mem. at 4; Defs.' Mem. at 5; Answer at 6. From 1914 to 1927, the Verona Band was recognized by the federal government as an Indian tribe. Pl.'s Mem. at 4-5; Defs.' Mem. at 5; Answer at 12-13. Neither Congress nor any executive agency ever formally withdrew federal recognition of the Verona Band. Pl.'s Mem. at 5; Answer at 14.
Nevertheless, after 1927, the federal government no longer acknowledged the Verona Band, or any past or present-day incarnation of the plaintiff, as a federally recognized tribal entity entitled to a government-to-government relationship with the United States.*fn5 Pl.'s Mem. at 5 (alleging that "sometime after 1927 the Department began to simply ignore the Tribe for many purposes and substantially reduced the benefits and services provided to the Tribe"); Answer at 3 (stating that "the Department does not recognize the Tribe and has not recognized it or any successor of it since 1927"). For example, Muwekma has never been included on the list of federally recognized tribes, first published by the Department in 1979. Pl.'s Mem. at 6; Answer at 14-15.
A. Federal Tribal Recognition
Federal recognition of tribal status "is a prerequisite to the protection, services, and benefits of the Federal government available to Indian tribes" and to the "immunities and privileges available to other federally acknowledged Indian tribes by virtue of their governmentto-government relationship with the United States." 25 C.F.R. § 83.2. Pursuant to statutorily delegated authority, the Department is empowered to determine which currently unrecognized tribes meet the criteria for federal recognition. 25 U.S.C. §§ 2, 9 (2000); see also James v. HHS, 824 F.2d 1132, 1137 (D.C. Cir. 1987) (stating that "Congress has specifically authorized the Executive Branch to prescribe regulations concerning Indian affairs and relations. The purpose of the regulatory scheme is to . . . determine which Indian groups exist as tribes") (citations omitted). Notably, Congress does not specify a procedure which the Department must follow to determine whether a petitioning Indian group is entitled to federal tribal recognition. Prior to 1978, such determinations were made on an ad hoc basis. Pl.'s Mem. at 9-10; Defs.' Mem. at 1 n.2. In 1978, however, the Department promulgated regulations that formally addressed the tribal recognition process. 43 Fed. Reg. 39, 361 (Sept. 5, 1978) (codified at 25 C.F.R. § 54 et seq.) (recodified at 25 C.F.R. § 83 et seq.). These regulations, which were revised in 1994, set forth seven "mandatory criteria," all of which must be satisfied in order for a petition for tribal acknowledgment under Part 83 to be successful. 25 C.F.R. § 83.7. The Part 83 criteria are as follows:
(a) The petitioner has been identified as an American Indian entity on a substantially continuous basis since 1900. . . .
(b) A predominant portion of the petitioning group comprises a distinct community and has existed as a community from historical times until the present. . . .
(c) The petitioner has maintained political influence or authority over its members as an autonomous entity from historical times until the present. . . .
(d) A copy of the group's present governing document including its membership criteria. . . .
(e) The petitioner's membership consists of individuals who descend from a historical Indian tribe or from historical Indian tribes which combined and functioned as a single autonomous political entity. . . .
(f) The membership of the petitioning group is composed principally of persons who are not members of any acknowledged North American Indian tribe. . . .
(g) Neither the petitioner nor its members are the subject of congressional legislation that has expressly terminated or forbidden the [f]ederal relationship.
Id. Until their 1994 revision, the regulations made no distinction between tribes that had been previously (but not currently) acknowledged and those that had never been federally acknowledged.*fn6 43 Fed. Reg. 39, 361 (Sept. 5, 1978) (codified at 25 C.F.R. § 54 et seq.) (stating that the regulations are "intended to cover only those American Indian groups . . . which are ethnically and culturally identifiable, but which are not currently acknowledged as Indian tribes by the Department"). The revised regulations, however, establish modified criteria for petitioning tribes that can provide substantial evidence of "[u]nambiguous previous [f]ederal acknowledgment." 25 C.F.R. § 83.8(a). Under the modified criteria, a previously acknowledged tribe needs only demonstrate, inter alia, (1) that it has been identified as an American Indian entity on a substantially continuous basis "since the point of [its] last [f]ederal acknowledgment," 25 C.F.R. § 83.8(d)(1); (2) that "it comprises a distinct community at present," 25 C.F.R. § 83.8(d)(2); and (3) that "political influence or authority is exercised within the group . . . from the point of [its] last [f]ederal acknowledgment to the present," 25 C.F.R. § 83.8(d)(3).
B. Muwekma's Petition for Acknowledgment
In early 1989, Muwekma submitted a letter of intent to petition for federal acknowledgment as an Indian tribe to the Department. Pl.'s Mem. at 11; Defs.' Mem. at 4. In its response, the Department directed Muwekma to file a formal petition for acknowledgment along with detailed documentation in accordance with the Part 83 criteria.*fn7 Pl.'s Mem., Exhibit ("Ex.") 46 (April 25, 1989 letter from Joseph Little to Rosemary Cambra) at 1 (cautioning Muwekma that "[b]ecause of the significance and permanence of acknowledgment as a tribe, the process of evaluation is a lengthy and thorough one"). Accordingly, beginning in 1995, Muwekma submitted a formal petition for acknowledgment as well as "thousands of pages" of supplemental material, Pl.'s Mem. at 11, comprising "primary and secondary source documents, genealogical evidence, arguments by its researchers, and responses to questions posed by the Department's staff," Defs.' Mem. at 5. After reviewing Muwekma's petition and the accompanying materials, the Department concluded preliminarily in May 1996 "that the Pleasanton or Verona Band of Alameda County[, from which members of the Muwekma tribe are directly descended,] was previously acknowledged by the federal government between 1914 and 1927." Defs.' Mem. at 5; see also Pl.'s Mem. at 11. The Department thus informed Muwekma "that it would be able to complete its petition documentation with the expectation that ...