7 the only legitimate and compelling government interests thus far identified for restricting campaign finances.”) (citation and internal quotation marks omitted). Importantly, the Court has emphasized that the anti-corruption rationale is not boundless. The core corruption that Government may permissibly target with campaign finance regulation “is the financial quid pro quo: dollars for political favors.” FEC v. Nat’l Conservative PAC (NCPAC), 470 U.S. 480, 497 (1985). This anticorruption interest is implicated by contributions to candidates: “To the extent that large contributions are given to secure a political quid pro quo from current and potential office holders, the integrity of our system of representative democracy is undermined.” Buckley, 424 U.S. at 26-27; see also Citizens Against Rent Control v. City of Berkeley, 454 U.S. 290, 296-97 (1981) (“Buckley identified a single narrow exception to the rule that limits on political activity were contrary to the First Amendment”; the exception relates “to the perception of undue influence of large contributors to a candidate”). Based on the close relationship between candidates and parties and record evidence demonstrating that political parties sold access to candidates in exchange for contributions, the Court has held that the anti-corruption interest also justifies limits on contributions to parties. See McConnell, 540 U.S. at 154; see also Buckley, 424 U.S. at 38.3 Fourth, in applying the anti-corruption rationale, the Court has afforded stronger protection to expenditures by citizens and groups (for example, for advertisements, get-outthe-vote efforts, and voter registration activities) than it has 3 Contributions include coordinated expenditures – that is, expenditures coordinated with a candidate or party. See McConnell, 540 U.S. at 121; FEC v. Colo. Republican Fed. Campaign Comm., 533 U.S. 431, 443 (2001); see also 2 U.S.C. § 441a(a)(7)(B).