They didn’t soulfully consider President Joe Biden’s marked decline and decide, for the good of him, his party and the country, that he had to step down.

They lied, and they got caught.

The Democratic Party line on Biden was that he had turned in an exceptionally effective State of the Union address. He might mess up a name here or there, but he had gotten better with age. He should be judged on his achievements, which rivaled those of LBJ. Anything suggesting he was in decline was a paranoid lie, or — in a truly ridiculous neologism — “a cheap fake.”

Everything we saw with our own eyes was misleading. No, he hadn’t wandered off at the G-7 summit. No, he hadn’t frozen up at his Hollywood fundraiser. No, he wasn’t having trouble walking and getting up the stairs of Air Force One.

No, everything was fine.

No one formally enforced this party line, but everyone knew to follow it — Democratic leaders, journalists and donors. The whispered conversations stayed whispered. Then, the debate happened, and the party line was inoperative.

There were attempts to revive it, but it was a little like being a Communist in the 1930s when Stalin wrenched the party into a totally new position. It didn’t matter whether the new line had any connection to the prior line; it had to be followed.

So, Joe Scarborough of MSNBC, who months earlier had issued forth with table-thumping assurances that Joe Biden was at the absolute top of his game, suddenly thought he might have to step aside.

George Clooney, who co-hosted the aforementioned Hollywood fundraiser, wrote in The New York Times that at that event, Biden was a shadow of his self, and suddenly former Obama speechwriter Jon Favreau could say that everyone he talked to at the event was appalled by Biden’s state.

The president can be forgiven for being disappointed and angry that everyone who had been covering for him switched overnight.

There’s no honor among thieves, but shouldn’t there be at least a little among political co-conspirators?

Biden showed monumentally poor judgment in deciding to run again last year. He almost certainly was in the grips of legitimate self-delusion, though. It’s natural that an old person who is in decline is the last to realize or admit it, and his belief that, on paper, he was a stronger candidate than Kamala Harris wasn’t crazy.

Biden’s enablers were the truly cynical and dishonest ones, hoping that their fake narrative about Biden’s continued vitality could see them through until November.

Their credibility should be shot as they make the switcheroo to Harris.

The same Democratic establishment that gave you Joe Biden without offering Democratic voters a legitimate choice (serious primary challengers were warned off this year), now is giving you Kamala Harris without offering Democratic voters a legitimate choice.

The same party that lied about Joe Biden without compunction or remorse now wants you to credit everything it is going to tell us about the marvelous, heretofore unappreciated qualities of Kamala Harris.

The same vice president who insisted, as of roughly the day before yesterday, that Joe Biden was the very picture of energy and effectiveness now wants us to believe everything else she’s going to say after he’s been forced from the race by his feeble state.

The same people who thought Joe Biden was incapable of doing interviews and teleprompter speeches on the campaign trail will tell us he’s perfectly capable of fulfilling his duties in the most trying job on the planet.

Finally, the same Democrats who were threatening Joe Biden with ignominy and exclusion if he stayed in the race a couple of more weeks now want us to buy their paeans to his great statesmanship.

In sum, the perpetrators of a shameful cover-up want us to move on as if nothing happened, when the stink of their rank deception should dog their candidate and their party the rest of this campaign.

Rich Lowry is editor of the National Review. Distributed by King Features Synd., Inc.