Marc Thiessen has written a column here at The Post arguing that President Trump is not, as most people acknowledge, the most prodigious liar in the history of the presidency, but in fact “may be remembered as the most honest president in modern American history,” because “when it comes to the real barometer of presidential truthfulness — keeping his promises — Trump is a paragon of honesty.”

Thiessen goes on to say that “When Trump says he will do something, you can take it to the bank.” And Wednesday morning, the column came to the attention of the president himself, the way he usually learns information: via “Fox & Friends.” So Trump tweeted this:

Thiessen is wrong about a number of things in this column, the first being that keeping promises is “the real barometer of presidential truthfulness.” It just isn’t — they’re somewhat related, but they aren’t the same thing at all. You can be honest and fail to keep your promises for any number of reasons, and Trump is living proof that you can keep promises while lying every step of the way. The assertion that the real measure of honesty is not honesty itself but something else sounds a lot like a concerted act of rationalization, a way of supporting a president who lies with shocking regularity while convincing yourself that you’re still a moral person for whom honesty matters.

But what I really want to address is Thiessen’s claim that Trump is perhaps “the most honest president in modern American history” because of his unparalleled record of promise-keeping. Trump has now endorsed this assessment, and it is a claim he will probably continue to make for, well, the rest of his life.

It’s a sweeping historical claim, and it would therefore require some grounding in history. Are the promises made in presidential campaigns usually kept or not? How did other presidents do at keeping their promises? Did they keep more or fewer than Trump has so far?

Remarkably, Thiessen doesn’t seem to have asked any of these questions. The only reference he makes to any previous president is to slap at Barack Obama for the way he sold the Affordable Care Act. Instead, he offers a list of things that Trump has done that he said he would do.

All of which is a perfectly good way of arguing that Trump has kept some promises. But Thiessen offers no evidence that Trump has kept more than presidents before him. In short, Thiessen makes a claim about Trump that is purely Trumpian, no different from when Trump says no president has accomplished more than him, or no one knows more about taxes than him, or no one knew health care could be so complicated before he figured it out.

The critical context for this discussion is that contrary to popular belief, most presidents keep most of their promises, in part because failing to do so is a good way to lose your reelection bid. This is something political scientists have known for some time — and tried without success to convince the public of.

But let’s get a bit more specific. Thiessen mentions Obama. PolitiFact tracked 533 promises Obama made, and judged that 48.4 percent were completely kept, another 27.4 percent were partially kept through a compromise, and 24.2 percent were broken, though “broken” is defined rather expansively. There are different kinds of broken promises: Some a president never intends to keep (such as Trump’s promise to make Mexico pay for a border wall), others he tries to keep but fails, usually because he runs into opposition in Congress (such as Obama’s promise to close Guantanamo), and others he makes a clear decision to break (such as George H.W. Bush’s promise not to raise taxes).

So according to PolitiFact, Obama kept about three-quarters of his promises in part or in full. And Trump? It has been tracking his promises too, and there the numbers are not quite as spectacular as Thiessen would have it. Trump has kept 13.7 percent of his promises and partially kept another 6.9 percent through compromise. Another 39.2 percent of the promises are “in the works,” meaning they might happen or might not, while 7.8 percent of the promises have been broken and 32.4 percent are “stalled,” meaning that if nothing changes, by the time he is done, those too will be “broken.”

You can disagree with PolitiFact’s judgment on what to include or what has happened, but its record for being nonpartisan is pretty solid, and at the very least, it provides a point of comparison, because it uses the same methods for assessing each presidency.

Reading Thiessen’s list of kept promises, you might be impressed at all the things Trump has done that he said he would do, and he waves away any question of broken promises by saying “Only in a few rare instances has he backtracked on a campaign pledge.” But is that true? Let’s look at a partial list of the things Trump has said he would do but hasn’t done:

  • Repeal the Affordable Care Act and replace it with “something terrific.”
  • Provide Americans with “insurance for everybody.”
  • Allow Medicare to negotiate drug prices.
  • Build a wall on the southern border and make Mexico pay for it.
  • Eliminate the “carried interest loophole” that benefits hedge fund managers.
  • Pass a massive infrastructure plan.
  • Officially declare China a currency manipulator.
  • Bring back the use of torture.
  • Sue the women who accused him of sexual misconduct.
  • Release his tax returns.
  • Appoint a special prosecutor to target Hillary Clinton.
  • Provide six weeks of paid leave to women who have children.
  • Eliminate the deficit and pay off the national debt.

Those are just a few of the promises Trump hasn’t kept — there are literally hundreds more, depending on what you want to include. And that only covers specific policy promises, not things such as Trump saying “I’m going to surround myself only with the best and most serious people,” then surrounding himself with a collection of charlatans and fools. It should be obvious that the idea that “When Trump says he will do something, you can take it to the bank” is patently ludicrous.

It will take another two (or six) years before we can fully judge how Trump compares to his predecessors. My guess is that when all is said and done, he will look much like other presidents in the proportion of promises he keeps. But at the moment, you can look at Trump’s promise-keeping glass as half empty or half full. We’re all subject to confirmation bias on this question like so many others, because it necessarily involves making subjective judgments about what matters. If you’re a Trump fan, you will laud him for what he followed through on and explain away what he didn’t by saying that he tried, or that it was the fault of Democrats, or that it wasn’t a serious promise in the first place.

But there is something absolutely perverse about saying that it’s fine for a president to constantly lie to the American people, literally thousands of times, as long as he follows through on some campaign pledges. What kind of morally warped standard is that? Would you accept it from anyone in your life — your spouse, your kids, your friends, your coworkers?

Of course not. And we shouldn’t accept it in a president.