In reality, the decision is a principled interpretation of the First Amendment that would have garnered wide support from many on the left just 30 years ago. What is truly frightening about the decision is that the four dissenting justices are promoting a vision of the First Amendment that is absolutely incompatible with limited government and free speech.
First, a little background. Since the mid-’70s, campaign finance law has been based on the core distinction between contributions and expenditures. Contributions go to candidates directly whereas expenditures are spent independently of candidates. In the seminal case of Buckley v. Valeo, the Court held that the government has a more compelling interest in regulating and limiting contributions than expenditures because of the threat of quid pro quo corruption, that is, the one-for-one exchange of contributions for political favors. In fact, preventing quid pro quo corruption is essentially the entire reason we have thousands of pages of campaign finance laws and regulations.
The Buckley decision thus upheld the limit on contributions to candidates, the so-called base limit, which is now $2,600. But there is another limit on contributions, the so-called aggregate limit, limiting the total amount that an individual can give to all candidates and political committees to which he contributes.
In the most basic sense, the question the Court was asked in McCutcheon was whether the aggregate contribution limit coupled with the individual contribution limit helps prevent quid pro quo corruption or whether it unjustifiably limits political speech. In the 2011–2012 election cycle, the plaintiff, Shaun McCutcheon, an Alabama businessman, had already contributed $33,088 to 16 candidates, but he wanted to contribute $1,776 to 12 more candidates, which would have pushed him over the aggregate limit. Given that every one of his contributions was below the individual limit, was it preventing any quid pro quo corruption to allow him to give $1,776 to eight more candidates, but not nine, 12, or 200? The obvious answer to that question seems to be “no,” and it is the answer that five of the nine justices gave, thus striking down the limit.