Mr. McCutcheon and the R.N.C. contend that the aggregate limits on contributions violate the First Amendment by constraining a contributor’s opportunity for political expression. This is unconvincing: Mr. McCutcheon is already permitted to spend as much money as he would like on his own independent campaign-related speech.

To get the full measure of how far-fetched Mr. McCutcheon’s claim is, consider his argument that aggregate contribution limits violate his right to political expression by preventing him from contributing the symbolic amount of $1,776 to each of 25 candidates (along with a total of $7,500 to three others) — though he could give $17.76 to every Republican Congressional candidate. It is as if the developers of One World Trade Center, which is 1,776 feet high, had argued that the First Amendment gave them the constitutional right to build to that height.

Though Mr. McCutcheon and the R.N.C. claim that they are not attacking all contribution limits, only aggregate limits, they know that in practice that is a distinction without a difference. If the court were to strike down aggregate limits, then a contributor could give money up to the maximum amount not only to every federal candidate but also to any political action committee that contributed to a candidate. And as a lower federal court in McCutcheon recognized, there is no limit on how many PACs might be created that are likely to contribute to a particular candidate.

If there were 10,000 PACs, all of which were likely to contribute to John Smith for Congress, then by Mr. McCutcheon’s and the R.N.C.’s reasoning you should be free to give up to the maximum of $5,000 to each PAC, for a total of $50 million. This would blow an enormous hole in the longstanding, court-approved scheme of campaign contribution limits.

As Justice Antonin Scalia once wrote in another context, this argument is not a wolf in sheep’s clothing: “this wolf comes as a wolf.” The only reason the Supreme Court would be tempted to let this wolf in is if the court wants to see the destruction of all limits on an individual’s donations to a political candidate.