They really shouldn’t:

The implication of this claim, though, is that if Hillary Clinton wins the election, Republicans will give her latitude to appoint a reasonably well-qualified, non-extreme jurist to the vacant spot. I have long been skeptical that Republicans would actually go along with this if it comes to pass. And now John McCain confirms it. In an interview touting fellow Republican Senator Pat Toomey, McCain pledges that he and his party will continue the Supreme Court blockade throughout Clinton’s term. “I promise you that we will be united against any Supreme Court nominee that Hillary Clinton, if she were president, would put up,” McCain said. “I promise you. This is where we need the majority and Pat Toomey is probably as articulate and effective on the floor of the Senate as anyone I have encountered.”

If Clinton wins and Democrats pull enough Senate seats, Republicans will oppose her nominee, and then, eventually, Democrats will change the rules to abolish filibusters of Supreme Court nominees. (Republicans will decry this foul measure and justify any subsequent actions of their own as justified revenge.) If Clinton wins and Republicans hold on to 51 seats, they will simply refuse to let any nominee through. The fact that it is McCain, a personal friend of Clinton and as strong an institutionalist as can be found in the Senate, who is proposing to extend the blockade indefinitely shows just how deep the commitment runs through the party.

Hold the line.