The high court rightly rejects an ominous election claim — but three justices dissent

As expected, the U.S. Supreme Court on Monday court decided not to hear a claim by Pennsylvania Republicans that the U.S. Constitution was violated by a Pennsylvania Supreme Court decision allowing some late-arriving mail ballots to be counted.

But three justices suggested that they might be open to arguments that state legislatures are supreme in election matters, even to the point of ignoring decisions by state supreme courts. The notion that legislatures have the final say in elections figured in then-President Trump’s efforts to overturn the results of last year’s...