Who can we believe regarding POTUS’s gutter mouth?

It’s come down to this: No longer can I take a single thing that Donald John Trump Sr. says at face value.

I do not believe unequivocally a single statement he can make.

Take his recent use of the term “sh**hole” to describe Africa, Haiti and El Salvador. He denies saying it. This morning, Sen. David Perdue, R-Ga., who was in the room when the president said it actually stood with Trump in his denial.

Others in the room — Sens. Lindsey Graham, R-S.C., and Dick Durbin, D-Ill. — said Trump used the term. Durbin said he uttered the term “repeatedly” while talking about immigration.

Trump’s lying is so pervasive, so inclusive, so very disturbing that I’ve crossed a key threshold that now casts into doubt every single utterance that flies out of his mouth.

My state of disbelief rivals how I used to feel about a one-time Amarillo, Texas, figure. I refer to the late Stanley Marsh 3, the eccentric millionaire artisan/lawyer/goofball who in his day did some mighty strange things.

The Weather Channel came here in the early 2000s to cover a weather-related event and while the TV weatherman was on the air, Marsh — while wearing a feathered head dress — started prancing around in the background doing some sort of Native American dance.

Marsh was the strangest of strange dudes. It got so weird that there came a time when there wasn’t a single thing one could say about Marsh that I could dismiss out of hand.

“Hey, did you hear that Stanley flew to Mars and brought a Martian back to Earth with him.” I always felt in the deepest part of my gut, “You know … I wouldn’t put it past him.”

And so it is with Donald Trump. The man has been heard in public using filthy language. He referred to pro football players protesting police conduct against African-Americans as “sons of bi*****. ” He has used what my father used to call “the functional four-letter word” on more than one occasion since becoming a politician. He has done the same with the scatological term as well.

So, when he denies calling certain nations of the world “sh**hole” countries, well … I don’t believe his denial.

The man is a liar.