20 NATIONAL REPUBLICAN SENATORIAL COMMITTEE v. FEDERAL ELECTION COMM’N Opinion of the Court First Amendment burden.” McCutcheon, 572 U. S., at 210 (quotation marks omitted). The base limits on contributions to candidates serve as an initial prophylaxis against quid pro quo corruption or its appearance in this context—after all, most contributions to candidates are not given in exchange for some official action. Id., at 221. The earmarking rules constitute a second prophylaxis. The disclosure requirements supply a third prophylaxis. So prophylaxis upon prophylaxis upon prophylaxis already serve to prevent quid pro quo corruption or its appearance. The political-party coordinated-expenditure limits at issue here would operate as a fourth line of defense. Such a “prophylaxis-upon-prophylaxis approach requires that we be particularly diligent in scrutinizing the law’s fit.” Ibid. (quotation marks omitted). But the fourth prophylaxis imposes a severe and direct restriction on free speech and infringes fundamental First Amendment values. Otherwise stated, the restriction on political-party coordinated expenditures is “disproportionate” and is not “necessary” and “narrowly tailored” to the Government’s interest in preventing circumvention of the base contribution limits. Id., at 199, 218, 220 (quotation marks omitted); Cruz, 596 U. S., at 306. On that last point, it is worth briefly focusing on the term “disproportionate” from McCutcheon. In this campaign finance context, determining how much regulation is enough to serve the Government’s asserted interest is not a scientific exercise. But in light of the First Amendment free-speech rights at stake, courts must be particularly vigilant. Courts cannot simply say, “what’s the harm in allowing just one more regulation” when that regulation would limit freedom of speech. On the contrary, courts must preserve and protect the freedom of speech guaranteed by the Framers. Necessary, narrowly tailored, and disproportionate may be technical legal terms, but they