Mr. Romney’s position is that Judge Jackson “more than meets the standard of excellence and integrity.” Ms. Murkowski aims to repudiate “the corrosive politicization” of these confirmations, which are getting “more detached from reality by the year.” Yet they will be disappointed if they imagine that their votes for Judge Jackson will buy any leeway for the next conservative Supreme Court nominee.

As Justice Antonin Scalia argued, if the High Court is going to be an activist institution that dictates abortion policy for 330 million people, then confirmation hearings are inevitably going to be partisan brawls. But distinctions are capable of being drawn. The claim that Judge Jackson was treated worse than Justice Kavanaugh, who was falsely accused of sexual assault, is dishonest. But that isn’t a hall pass for unfortunate Republican behavior.

Take the floor speech this week by Sen. Tom Cotton. “The last Judge Jackson,” he said, referring to Justice Robert Jackson, “left the Supreme Court to go to Nuremberg and prosecute the case against the Nazis. This Judge Jackson might have gone there to defend them.” Bringing up the Nazis, based on a coincidence of somebody’s last name, is an embarrassing moment for Mr. Cotton.

Republicans shouldn’t forget who is to blame for their predicament. If President Trump hadn’t been preoccupied with imagined fraud conspiracies after the 2020 election, Republicans probably would have retained two Senate seats in the January 2021 Georgia runoff elections. Without Democratic Senate control, President Biden might have been forced to choose a more moderate nominee than Judge Jackson, or possibly a jurist older than age 51, with a shorter prospective Supreme Court career.

Conservatives could spend the next 30 years ruing Justice Jackson’s decisions. Spare a thought for how Mr. Trump helped it happen.