“I KNOW of no example in American history of a moment where the leader and the American people came together as fast as they have in the last year with Donald Trump,” former House speaker Newt Gingrich said. “He is someone who has connected with everyday Americans like no one since Ronald Reagan,” Indiana Gov. Mike Pence said. He “is the person who I firmly believe will serve this country best,” New Jersey Gov. Chris Christie said.

In every presidential election, politicians campaign to become their party’s vice presidential pick, often by heaping undeserved praise on their party’s presidential nominee. It is rarely more than mildly embarrassing. But when the presidential candidate is Donald Trump, the slobbering is repulsive.

Every time they praise Mr. Trump’s leadership skills, these political opportunists should be asked about the candidate’s apparent ignorance of the Constitution and his contempt for essential principles such as freedom of speech. Every time they talk about how Mr. Trump would keep Americans safe, they should be asked about which Americans they mean — surely not minority groups who would feel under constant scrutiny and threat in Mr. Trump’s America. Every time they attack Hillary Clinton for dishonesty, they should be asked about Mr. Trump’s constant, flagrant lying about basic facts, as when he claimed that he saw thousands of American Muslims celebrating the 9/11 attacks.

For good measure, they should also be asked how they could support a man they know is unqualified to be commander in chief. Before endorsing Mr. Trump, Mr. Christie criticized him for acting “like a child” and insisted he is not “suited to be president of the United States.” National Review reported that Mr. Pence privately loathes the presumptive GOP nominee. Mr. Gingrich called Mr. Trump’s attacks on a judge for his ethnicity “inexcusable.”

Treating Mr. Trump as a normal candidate is a grave insult to the country’s democratic tradition. This election year presents an unusually clear moral choice. Not only are Mr. Trump’s supplicants on the wrong side of history, but they are also actively and knowingly aiding the candidacy of an unacceptable, dangerous demagogue for their own personal gain. The fact that Mr. Trump’s vice presidential shortlist contains two unpopular governors and a disgraced ex-speaker of the House shows that his judgment is as poor as it seems to be or, more likely, that only desperate, unprincipled panderers would consider joining his ticket.