At the end of June the Supreme Court decided, in National Republican Senatorial Committee v. Federal Election Commission , that federal limits on political parties’ campaign spending violated the First Amendment—in effect overruling a twenty-five-year-old campaign finance precedent. Now parties are free to spend unlimited sums in coordination with candidates. Since donors may give a national party committee twelve times more than they can contribute to a candidate directly, these larger checks can now find their way to the campaigns the donor favors.

The decision was one more attack by the Court on long-standing rules to limit money in politics. The effort began in earnest with the Court’s landmark 2010 ruling in Citizens United v. FEC , which legalized unlimited independent political spending by corporations, labor unions, and other associations.…