Donald Trump just may be our most honest president since Abraham Lincoln.

Sure, the Washington Post’s valiant if pedantic fact-checkers claim that “In 710 days, President Trump has made 7,645 false or misleading claims.” The Post’s Glenn Kessler even introduced a new rating for the Trump era, the “bottomless Pinocchio,” for a false claim repeated over and over again.

The competing fact-checkers over at Politifact have five long pages of what they term “pants on fire!” statements from Mr. Trump. The president “has a well-documented problem telling the truth,” The New York Times insists. Even before Mr. Trump took office, his trustworthiness about personal matters ranging from his marital fidelity to his wealth was widely doubted.

Another dimension of integrity, though, doesn’t involve precision about details or about anything personal. It has to do with the president’s commitment to following through on his campaign pledges. In that department, Mr. Trump has been astonishingly, almost unprecedentedly faithful.

The partial government “shutdown” underway in Washington can best be understood as Mr. Trump attempting to be true to his word to voters that he would build a wall along the border with Mexico to prevent illegal immigration.

It’s baffling to longtime Washington observers, who have a hard time conceiving of a president shutting down the government over something as trivial as a mere campaign promise.

Mr. Trump’s recent decision to withdraw American troops from Syria — walked back some over the weekend by the national security adviser, John Bolton — is likewise best understood in the framework of Mr. Trump attempting to keep true to his campaign themes.

If you’ve forgotten Mr. Trump’s 2016 campaign speeches, the American Presidency Project at University of California Santa Barbara has a selection of them available. In a November 2, 2016, appearance in Orlando, Fla., Mr. Trump said, “we will build a great wall.”

In the same appearance, Trump said, “Hillary and our failed Washington establishment have spend $6 trillion on wars in the Middle East that we never won and that never end. And it’s now in worse shape than ever before. The Middle East is a catastrophe, it’s far worse off than had we spent nothing. They’ve dragged us into foreign wars that have made us less safe.”

In that same Orlando speech, Mr. Trump said, “A Trump administration will renegotiate NAFTA.” He did that. He also said, “We will also immediately stop the job killing Trans-Pacific Partnership.” He did that, too. In the Orlando speech, Mr. Trump said, “we’re going to lower taxes on American business from 35 percent to 15 percent.” He did win a reduction of the corporate tax rate to 21%.

Mr. Trump promised during the presidential campaign to nominate a Supreme Court justice from a list of names released before the election, and he kept that promise with Neil Gorsuch. He said during the presidential campaign that he would move the American embassy to Israel’s capital, Jerusalem, and he kept that promise, too. He said in the campaign that he’d scrap the Iran nuclear deal, and he indeed has.

There’s something admirable about a politician keeping his word to this degree. It’s also exceedingly rare, especially recently. George H.W. Bush ran on a “read my lips” pledge against tax increases; he turned around and broke it.

Bill Clinton campaigned in 1992 promising a middle class tax cut; once in office, in 1993, he signed into law a tax increase. George W. Bush ran promising a “humble” foreign policy but cast that approach aside after the terrorist attacks of September 11, 2001. Mr. Bush also failed to deliver on the Social Security reform he campaigned on, though it wasn’t for lack of trying.

Our greatest presidents have reputations for integrity that have endured to this day, from the cherry tree myth about George Washington (“I cannot tell a lie”) to the stories about “Honest Abe” Lincoln. It’s certainly not yet clear that Mr. Trump is in Washington or Lincoln’s class. Few presidents are.

Though Mr. Trump does seems to be trying, he’ll eventually be judged more on results than on effort. No new physical border barrier has been fully built. American troops have not ended their deployments overseas.

Regardless of what anyone’s individual personal views are on either the wall or the troops in Syria, the only one who has been elected president of the United States on the basis of his stated view of those issues is Donald Trump.

One needn’t be an advocate of the border wall or an opponent of the Syria deployment or even a fan of Mr. Trump to appreciate that it’s actually good for democracy when politicians, after elections, try to keep the promises they made during campaigns. When such promises are quickly or easily abandoned, it risks breeding voter cynicism, disillusionment, and disengagement.

Why even bother listening to political rhetoric if what the candidates say bears no resemblance to what they eventually do? If Mr. Trump, in at least this particular way, is not corrupt, it’s a kind of honesty that’s important — maybe even more important than some of the misstatements for which he has been faulted. Call him the promise-keeper president.