Cite as: 572 U. S. ____ (2014) 33 Opinion of ROBERTS, C. J. explained, “restrictions on direct contributions are preventative, because few if any contributions to candidates will involve quid pro quo arrangements.” Citizens United, 558 U. S., at 357. The aggregate limits are then layered on top, ostensibly to prevent circumvention of the base limits. This “prophylaxis-upon-prophylaxis approach” requires that we be particularly diligent in scrutinizing the law’s fit. Wisconsin Right to Life, 551 U. S., at 479 (opinion of ROBERTS, C. J.); see McConnell, 540 U. S., at 268–269 (opinion of THOMAS, J.). 2 Importantly, there are multiple alternatives available to Congress that would serve the Government’s anticircumvention interest, while avoiding “unnecessary abridgment” of First Amendment rights. Buckley, 424 U. S., at 25. The most obvious might involve targeted restrictions on transfers among candidates and political committees. There are currently no such limits on transfers among party committees and from candidates to party committees. See 2 U. S. C. §441a(a)(4); 11 CFR §113.2(c). Perhaps for that reason, a central concern of the District Court, the Government, multiple amici curiae, and the dissent has been the ability of party committees to transfer money freely. If Congress agrees that this is problematic, it might tighten its permissive transfer rules. Doing so would impose a lesser burden on First Amendment rights, as compared to aggregate limits that flatly ban contributions beyond certain levels. And while the Government has not conceded that transfer restrictions would be a perfect substitute for the aggregate limits, it has recognized that they would mitigate the risk of circumvention. See Tr. of Oral Arg. 29. One possible option for restricting transfers would be to require contributions above the current aggregate limits to be deposited into segregated, nontransferable accounts