Cite as: 572 U. S. ____ (2014) 7 Opinion of ROBERTS, C. J. limits “as a coherent system rather than merely a collection of individual limits stacking prophylaxis upon prophylaxis.” Ibid. McCutcheon and the RNC appealed directly to this Court, as authorized by law. 28 U. S. C. §1253. In such a case, “we ha[ve] no discretion to refuse adjudication of the case on its merits,” Hicks v. Miranda, 422 U. S. 332, 344 (1975), and accordingly we noted probable jurisdiction. 568 U. S. ___ (2013). II A Buckley v. Valeo, 424 U. S. 1, presented this Court with its first opportunity to evaluate the constitutionality of the original contribution and expenditure limits set forth in FECA. FECA imposed a $1,000 per election base limit on contributions from an individual to a federal candidate. It also imposed a $25,000 per year aggregate limit on all contributions from an individual to candidates or political committees. 18 U. S. C. §§608(b)(1), 608(b)(3) (1970 ed., Supp. IV). On the expenditures side, FECA imposed limits on both independent expenditures and candidates’ overall campaign expenditures. §§608(e)(1), 608(c). Buckley recognized that “contribution and expenditure limitations operate in an area of the most fundamental First Amendment activities.” 424 U. S., at 14. But it distinguished expenditure limits from contribution limits based on the degree to which each encroaches upon protected First Amendment interests. Expenditure limits, the Court explained, “necessarily reduce[ ] the quantity of expression by restricting the number of issues discussed, the depth of their exploration, and the size of the audience reached.” Id., at 19. The Court thus subjected expenditure limits to “the exacting scrutiny applicable to limitations on core First Amendment rights of political expression.” Id., at 44–45. Under exacting scrutiny, the