“The American people‎ should have a voice in the selection of their next Supreme Court justice. Therefore, this vacancy should not be filled until we have a new president,” Mr. McConnell said in a statement released the night Justice Scalia died.

“All we are doing is following the longstanding tradition of not fulfilling a nomination in the middle of a presidential year,” he said in a March 2016 interview with Fox News Sunday.

Mr. McConnell’s claim then of keeping to tradition was incorrect, given that the Senate has rejected a Supreme Court nominee one other time in an outgoing president’s final months in modern history. And Democrats have a point in noting now that the crux of Mr. McConnell’s argument — to give voters a say in the process — could also apply to the midterm elections since senators must confirm Supreme Court nominations.

Still, it is clear from statements, news conferences, interviews and in speeches on the Senate floor, Mr. McConnell consistently and specifically said that “the presidential election process” — and not “a lame-duck president” — should decide the next Supreme Court justice.