President Trump told assembled construction workers that he intends to "rebuild" America, at the 2017 North America's Building Trades Unions National Legislative Conference on April 4 in Washington. (Peter Stevenson/The Washington Post)

From William McGurn, a conservative columnist at the conservative Wall Street Journal, comes some conservative advice for Democrats: “You don’t win votes by showing contempt for voters.” It is a nice sentiment, but as the last presidential election proved, it is wrong. Just as surely as the hapless Blanche DuBois in “A Streetcar Named Desire” said she always “depended on the kindness of strangers,” so did Donald Trump rely on the gullibility of the electorate. Nothing shows contempt for the voters more than the willingness to lie to them.

Trump guaranteed that he would repeal and replace Obamacare. So far, he has failed to do either. It is still early in his tenure and so this promise cannot be ruled out, but it stood a better chance back when Trump had not yet revealed that he was fabulously incompetent at dealing with Congress. I am not even sure he knows where it is. He promised not just to repeal Obamacare but also to offer all Americans the kind of health-care coverage that he could hardly envisage and never fund. Still, millions of Americans, their eyes moist in gratitude, took the man at his word. It was touching.

Trump promised to build a wall between the United States and Mexico. This has not been done. Trump further promised to somehow get the Mexicans to pay for the wall. For some reason, they have not complied. The wall was conceived as a way of shutting down illegal immigration from Mexico, which was the cause of all sorts of maladies, including rape. The wall would not only protect American jobs but also protect American womankind, much as racial segregation was supposed to do in the dewy, dippy South of old. So far, no wall. So far, no willingness of Mexico to pay for it. So far, not much in the way of illegal Mexican immigration. A lot of Mexicans are, in fact, heading the other way.

Trump was going to move the U.S. Embassy from Tel Aviv to Jerusalem. I think this was another thing he was going to do on Day One, but he was very busy counting the inaugural crowd that day, and the embassy, understandably, probably slipped his mind. Just the other day, though, the administration conceded that the embassy is staying where it is — for the time being, of course.

Most important, Trump promised to dismantle all sorts of trade and climate deals and bring back jobs and everything else to the United States. He has repudiated the Paris climate agreement, fulfilling a promise but not the reason for it. As with his vows regarding trade, none of his actions is going to bring jobs back to the United States. He promoted the American coal miner as the guy who took a sucker punch from the Obama administration and its obsession with globalization, but in this industry as in others, if the jobs are coming back, they are coming back as jobs for robots or jobs in alternative industries. Solar energy is a growing field; coal mining is not. Trump either knows this or ought to have known it: When he made common bond with miners — when he talked just recently about favoring Pittsburgh over Paris — he was showing astounding contempt for people who have lost their livelihoods. The job are gone and so, in Trump’s case, is truth.

Despite what conservative commentators persist in writing, I and others of my ilk have no contempt for Trump voters — most of them, anyway. (I reserve my contempt for those who knew that the man was an unbalanced fool but voted for him anyway, hoping that he’d lower their taxes.) But the voters who believed what they were told, who had their animosities and prejudices validated — who thought jobs were a-coming and Mexicans would be a-leaving and embassies would move and China would fall into line and the Islamic State would fall entirely — have my sympathy and political condolences. You won, but as you soon will discover, you lost.

Big.