In recent years, the Supreme Court has issued a spate of generally good campaign finance decisions that move steadily closer to treating free speech the way it should be treated — as an individual right. Last week’s decision in McCutcheon v. FEC, which struck down so-called “aggregate” contribution limits, is the latest example. As Chief Justice Roberts noted in his decision for the Court, aggregate limits, which cap the total amount that anyone can give to all candidates and committees during an election season, end up limiting the overall number of candidates one can support. “The government may no more restrict how many candidates or causes a donor may support than it may tell a newspaper how many candidates it may endorse.”

This point isn’t hard to grasp. If we have the right to speak out about politics and to support candidates, then surely a limit on the number of candidates we can support or the amounts we can spend on speech violate that right.

So why do so many people — including the four liberal justices on the Supreme Court — insist that campaign finance laws are constitutional? Under what theory can the laws be reconciled with the First Amendment?