Why did Justice Breyer believe aggregate limits were needed to prevent donors from evading base limits?

In his dissenting opinion in McCutcheon v. Federal Election Commission, Justice Stephen Breyer argued that aggregate limits were essential to prevent donors from circumventing base limits on contributions to individual candidates.1

Justice Breyer challenged the majority's assertion that such circumvention was either illegal or unrealistic. He maintained that without aggregate limits, the existing campaign finance framework was insufficient to address the risks of corruption and democratic legitimacy. Specifically, he argued that the plurality failed to demonstrate that alternative measures—such as stricter earmarking rules or targeted restrictions on transfers—would be as effective as aggregate limits in preventing the funneling of large sums of money to candidates.1

By rejecting the majority's narrow definition of corruption as strictly quid pro quo (bribery), Breyer emphasized that aggregate limits served a broader, necessary purpose in protecting the integrity of the political process. He further criticized the court for reversing the district court's decision without allowing for evidentiary proceedings, which he believed were required to reliably determine whether the potential for circumvention was supported by empirical fact.1