The district court already made a determination as to admissibility, albeit under a different standard than we apply on remand, and granted summary judgment based on its exclusion of plaintiffs' expert testimony. Daubert v. Merrell Dow Pharmaceuticals, Inc., 727 F. Supp. 570, 575-76 (S.D.Cal. 1989). A grant of summary judgment may be sustained on any basis supported by the record, Leonard v. Clark, 12 F.3d 885, 889 (9th Cir. 1993), so we shall consider whether the district court's grant of summary judgment can be sustained under the new standard announced by the Supreme Court. Our review here is, of course, very narrow: We will affirm the summary judgment only if, as a matter of law, the proffered evidence would have to be excluded at trial.

Where waivers are permissible, they are often enforced only if the waiver was "knowing" or "intelligent," which means the individual has "sufficient awareness of the relevant circumstances and likely consequences" of his decision, Brady v. United States, 397 U.S. 742, 748, 90 S.Ct. 1463, 25 L.Ed.2d 747 (1970). See generally United States v. Navarro-Botello, 912 F.2d 318, 321 (9th Cir. 1990) ("A knowing and voluntary waiver of a statutory right is enforceable.") (emphasis added); United States v. Michlin, 34 F.3d 896, 898 (9th Cir. 1994) ("A knowing and voluntary waiver is a prerequisite to our enforcement of a plea agreement waiving appellate rights."); Leonard v. Clark, 12 F.3d 885, 889-90 (9th Cir. 1993) ("First Amendment rights may be waived upon clear and convincing evidence that the waiver is knowing, voluntary and intelligent."). We conclude that a heightened standard of voluntariness is appropriate here because the statute now before us measures the behavior of debt collectors under the rubric of the "least sophisticated debtor."

“The general rule applicable to federal court suits with multiple plaintiffs is that once the court determines that one of the plaintiffs has standing, it need not decide the standing of the others.” Leonard v. Clark, 12 F.3d 885, 888 (9th Cir.1993). B.

Because we conclude that Public Lands Council has standing, we need not consider whether American Farm Bureau Federation also has standing. See Leonard v. Clark, 12 F.3d 885, 888 (9th Cir. 1993). Intervenors also challenge Plaintiffs' standing to assert their claims.

Because we hold that Buono has standing, we need not also evaluate Schwartz's standing. See Leonard v. Clark, 12 F.3d 885, 888 (9th Cir. 1993) ("The general rule applicable to federal court suits with multiple plaintiffs is that once the court determines that one of the plaintiffs has standing, it need not decide the standing of the others." (citing Carey v. Population Servs. Int'l, 431 U.S. 678, 682, 97 S.Ct. 2010, 52 L.Ed.2d 675 (1977))).

If a conviction is constitutionally required, the fact that two of the six plaintiffs were convicted suffices to establish standing for all. See Leonard v. Clark, 12 F.3d 885, 888 (9th Cir. 1993), as amended. Thus the City's argument that Appellants lack standing because a conviction is required fails on the facts as well as the law.

Thus, in Leonard v. Clark, we held that individual firemen did not have standing to challenge a portion of their union's collective bargaining agreement because the provision at issue "by its plain language applie[d] only to the Union and not to its individual members." 12 F.3d 885, 888-89 (9th Cir. 1994); see also Getman, 328 F.3d at 1095 (indicating that a plaintiff has not established an injury in fact where the statute "clearly fails to cover [the plaintiffs] conduct" (quoting Majors v. AMI, 317 F.3d 719, 721 (7th Cir. 2003))). Likewise, we have held that plaintiffs did not demonstrate the necessary injury in fact where the enforcing authority expressly interpreted the challenged law as not applying to the plaintiffs' activities.

Because we conclude that Preminger has direct standing to bring an as-applied challenge, we need not and do not consider whether the Santa Clara County Democratic Central Committee has standing and whether either Plaintiff has associational or third-party standing. See Leonard v. Clark, 12 F.3d 885, 888 (9th Cir. 1993) ("The general rule applicable to federal court suits with multiple plaintiffs is that once the court determines that one of the plaintiffs has standing, it need not decide the standing of the others."). B. The VA's application of the Regulation did not violate the First Amendment.

However, any such waiver must be made "voluntarily, knowingly, and intelligently." Marsh, 105 F.3d at 111; see Lake James Community Volunteer Fire Dep't, Inc. v. Burke County, 149 F.3d 277, 280 (4th Cir. 1998), cert. denied, 525 U.S. 1106, 119 S.Ct. 874, 142 L.Ed.2d 775 (1999); United States v. Local 1804-1, 44 F.3d 1091, 1098 n. 4 (2d Cir. 1995); Leonard v. Clark, 12 F.3d 885, 889-90 (9th Cir. 1993); Erie Telecommunications, 853 F.2d at 1094; Sambo's Restaurants, 663 F.2d at 690. Moreover, the waiver must be established by "clear and compelling" evidence.

"The general rule applicable to federal court suits with multiple plaintiffs is that once the court determines that one of the plaintiffs has standing, it need not decide the standing of the others." Leonard v. Clark, 12 F.3d 885, 888 (9th Cir. 1993). In this case, we have no doubt that several of the petitioners, at least, have standing to challenge the implementation of AB 5.