Judge Neil Gorsuch, President Trump’s nominee for the Supreme Court, must publicly condemn the president’s attack on the judge who blocked his immigration order. Judge Gorsuch’s sterling credentials notwithstanding, his supporters in the legal community should withdraw their backing for his nomination if he fails to do so.

After Judge James Robart’s ruling Friday evening, Mr. Trump wrote on Twitter, “The opinion of this so-called judge, which essentially takes law-enforcement away from our country, is ridiculous and will be overturned!” Mr. Trump may be right that the order will be stayed or overturned — the legal merits are tricky, and Judge Robart has not heard full briefing of them yet. But the attack on Judge Robart’s integrity is indefensible.

Federal judges have frustrated American presidents since the founding. Thomas Jefferson fulminated against judicial overreach and tried to get a Supreme Court justice impeached. Andrew Jackson disregarded a judicial order from the Supreme Court, Abraham Lincoln suspended the writ of habeas corpus and Franklin D. Roosevelt tried to pack the Supreme Court with his own appointees after it blocked many of his New Deal reforms. In his 2010 State of the Union address, President Obama criticized an opinion of the Supreme Court on campaign finance reform in front of some of the justices.

But, by and large, presidents have respected the federal judiciary. As far as I know, no president has publicly challenged the integrity of a judge who has ruled against him. Mr. Trump, as in so many other cases, has broken new ground.