Donald Trump isn’t very good at the job of being president, but there is one thing he does really well: He displays excellent message discipline behind the claim that he’s good at keeping promises. He mentions it all the time and reportedly has a list that he hands out to Oval Office visitors about all the things he says he’s followed through on. In fact, he’s so good at this that Jim VandeHei over at Axios bought the idea that “one of President Trump’s underappreciated re-election assets is something all politicians promise but few do: He has largely done precisely what he promised his base he would do.”

I’m very tempted to begin with a joke about the missing platform plank about buying Greenland. It is fair to say, however, that Mr. Trump is good at convincing people that he’s doing what he said he would do. But it’s not true at all that “few” politicians keep or even try to keep their promises. In fact, it turns out that most politicians, and most presidents, actually try hard to do in office what they said they would do on the campaign trail.

The best recent example of this before Mr. Trump is the Affordable Care Act. Barack Obama campaigned on it as a top priority and wound up supporting a law that looked an awful lot like what he (and other leading Democratic contenders in 2008) sketched out during the race. There are, of course, some well-known counterexamples — George H.W. Bush famously broke his “no new taxes” pledge — but over all, there’s plenty of evidence that politicians try to keep their promises.

Mr. Trump is very good at framing his actions with respect to his promises, but whether he is actually better or worse than most presidents at doing what he said he would do is a complicated question. It’s especially hard to assess Mr. Trump on this because his pre-election comments were all over the place on topic after topic. Should we judge him on his promise to end Middle Eastern wars — or his comments that the United States should “take out” the families of terrorists and “take” Iraqi oil? On getting rid of Obamacare (well, he tried) or on having a “beautiful” health care plan (he hasn’t actually had one, although he did at times support congressional Republican plans that didn’t do the things he said his nonexistent plan would do)?