PRESIDENT TRUMP’S scorn for the rule of law has — by now — been pretty well established. He has denigrated the FBI, impugned the motives of judges, attacked the investigation into his campaign’s involvement with a foreign adversary, repeatedly ridiculed his attorney general and called for political rivals to be imprisoned. But his latest tweeted tirade over the Justice Department’s decision to bring criminal charges against two Republican congressmen represents a grotesque new low that should alarm anyone who cares about our democracy.

A pair of tweets Monday by Mr. Trump criticized Attorney General Jeff Sessions for bringing corruption charges against two “very popular” Republican lawmakers so close to November because, he suggested, it hurts the GOP’s chances of holding the House. “Two easy wins now in doubt because there is not enough time. Good job Jeff,” the president tweeted in apparent reference to the indictments of Rep. Duncan D. Hunter (Calif.) and Rep. Chris Collins (N.Y.). Mr. Hunter and his wife, Margaret, have been charged with using more than $250,000 in campaign funds for personal expenses, and Mr. Collins has been charged with insider trading. Both lawmakers pleaded not guilty: Mr. Hunter is still running for reelection, while Mr. Collins suspended his campaign.

Here is the president of the United States — responsible for the execution and enforcement of laws — openly putting party before justice, caring not about wrongdoing but rather about losing votes and maybe congressional seats. A justice system that is used to protect allies and punish enemies may be the norm of authoritarian governments. But, as Sen. Ben Sasse (R-Neb.) said in a pointed statement, “The United States is not some banana republic with a two-tiered system of justice — one for the majority and one for the minority party. These two men have been charged with crimes because of evidence, not because of who the President was when the investigations began.” Sen. Jeff Flake (R-Ariz.) also joined in rebuking the president, tweeting, “This is not the conduct of a President committed to defending and upholding the Constitution, but rather a President looking to use the Department of Justice to settle political scores.”

Credit to Mr. Sasse and Mr. Flake for speaking out — but where is the rest of the Republican Party? A spokeswoman for House Speaker Paul D. Ryan (R-Wis.) did manage to tell CNN that the Justice Department “should always remain apolitical, and the speaker has demonstrated he takes these charges [against Mr. Collins and Mr. Hunter] seriously.” But most GOP lawmakers stayed silent, and it was hard not to contrast their reticence with the homage many of them paid just days earlier to the late Republican senator John McCain for always putting country over party. What do they think Mr. McCain would say about a president who wanted to use the Justice Department to go after his enemies and protect his friends?

The continuing failure of Republicans to provide a check on this president makes the upcoming midterm elections all the more important. Congress needs leaders who will resist Mr. Trump’s assaults on the rule of law.