For one thing, politicians used to limit their outright lies to matters not easily checked — hidden affairs, under the table deals, and so on. But now we have the man who ran the Miss Universe competition in Moscow three years ago, and who declared just last year that “I know Russia well,” then last month said, “I haven’t called Russia in 10 years.”

On matters of policy, politicians used to limit their misrepresentations of facts and impacts to relatively hard-to-verify assertions. When George W. Bush insisted that his tax cuts mainly went to the middle class, this wasn’t true, but it took some number-crunching to show that. Mr. Trump, however, makes claims like his assertion that the murder rate — which ticked up in 2015 but is still barely half what it was in 1990 — is at a 45-year high. Furthermore, he just keeps repeating such claims after they’ve been debunked.

And the question is, who’s going to stop him?

The moral vacuity of Republicans in Congress, and the unlikelihood that they’ll act as any check on the president, becomes clearer with each passing day. Even the real possibility that we’re facing subversion by agents of a foreign power, and that top officials are part of the story, doesn’t seem to faze them as long as they can get tax cuts for the rich and benefit cuts for the poor.

Meanwhile, Republican primary election voters, who are the real arbiters when polarized and/or gerrymandered districts make the general election irrelevant for many politicians, live in a Fox News bubble into which awkward truths never penetrate.

And what about the Fourth Estate? Will it let us down, too?

To be fair, the first weeks of the Trump administration have in important ways been glory days for journalism; one must honor the professionalism and courage of the reporters who have been ferreting out the secrets this authoritarian-minded clique is so determined to keep.

But then you watch something like the way much of the news media responded to Mr. Trump’s congressional address, and you feel despair. It was a speech filled with falsehoods and vile policy proposals, but read calmly off the teleprompter — and suddenly everyone was declaring the liar in chief “presidential.”

The point is that if that’s all it takes to exonerate the most dishonest man ever to hold high office in America, we’re doomed. Let’s hope it doesn’t happen again.