I truly admire the mendacity of Donald Trump’s supporters who contend that his “success” comes from his being a non-politician.

A number of my many social media contacts keep telling me that falsehood. One of them wrote recently: He’s not a politician. That’s why he’s getting things done in D.C.

OK, let’s go to the trusty, handy-dandy source upon which I rely to answer key questions, such as: How do you define a politician?

I cracked open my American Heritage Dictionary, where I found this: “One actively involved in politics.”

Now, maybe a I am quibbling just a bit, but to my way of thinking that makes Donald Trump every bit the politician.

Trump joined the politicians’ ranks when he rode down that gilded elevator in Trump Tower in 2015 to announce he would run for president of the United States.

I am going to acknowledge the obvious. Trump’s entire adult life prior to that moment had been dedicated to self-enrichment. Public service was nowhere to be found on his resume. His background was replete with business dealings, most of which produced — at best — mixed results.

He got that big stake from his father to get him started in the real estate development business. Then the dookey hit the fan with all those failed ventures: the steaks, the hooch, assorted resorts, the university … whatever.

So he brought that spotty record, along with his reality TV and beauty pageant experience with him into the only political campaign he’s ever launched.

I get that he wasn’t a pol prior to running for political office, but the moment he entered politics, Donald Trump became a practitioner of the profession.

He became a politician.

If the Trump acolytes who continue to insist that his “success” is due to his non-political background, go easy on that one, folks. The record isn’t so gleaming.