Donald Trump won the presidency by hopping a ride on any cockamamie claim bouncing around the Internet.

Now Trump is at it again, this time demonstrating stunning irresponsibility.

You would hope that a president-elect would never trot out a baseless allegation that undermines public confidence in American elections just to score a cheap political point. But you would hope wrong.

EDITORIAL

On Sunday, Trump spent a good part of his day tweeting out fact-free conspiracy charges of voter fraud — in an election that he won. He did so because it annoys him that Green Party presidential nominee Jill Stein has requested recounts in three states and raised the money to pay for them. It annoys him further that Hillary Clinton will be sending lawyers to monitor the recounts.

In a weekend tweetstorm, Trump asserted, “In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally.”

There is zero evidence of this. Every objective analysis has concluded this was a clean election, as national elections in the United States are, with fraud kept to an insignificant minimum.

Trump should be happy about this. It means, among other things, that he almost certainly will prevail in any recount. But Trump is Trump; his fragile ego requires that he hit back. Facts and truth be damned.

So where did Trump come by this notion of massive voter fraud?

Quite likely, reports Politico, Trump is parroting the line of the right-wing website Infowars, which reported two weeks ago — based on nothing — that three million votes were cast “by illegal aliens.” Infowars is run by the conspiracy-crazy radio host Alex Jones, who, as you may recall, also has said the Sandy Hook Elementary School shooting in 2012, in which 20 children died, was a hoax.

Trump hitched a ride on a train of nonsense to win the White House, and we learned Sunday that he is not about to quit. He fanned the “birther” conspiracy that Barack Obama was born in Kenya. He speculated that the father of Sen. Ted Cruz conspired in the assassination of President John F. Kennedy. He retweeted with approval the silly claim that Obama wears a secret Muslim ring.

Recently, The Washington Post tallied up 58 Trump conspiracy theories. As of Sunday, make that 59.

Donald Trump, soon to be leader of the Free World, either believes any stupid thing or, though knowing better, says any stupid thing.

Either way, we’re in for a long four years.

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