Among the many things Donald Trump promised while running for president — in addition to “making America great again” and throwing out illegal immigrants — was that he would upset the political norm.

He would be an “unconventional president.” Boy howdy! He has delivered on that one! I now want to offer an example.

He has turned political adversaries who otherwise would be friends into, well, bitter enemies.

My friends have known my political leanings for a long time. They tilt leftward. I favor Democrats over Republicans at the highest levels of government; I have voted all Democrat for president in every election since 1972. I do split my ticket, though, and I have voted for many Republicans at state and local levels over that span of time.

I have many friends who have voted all Republican for president. We have remained friends. However, I must admit that our friendship has been undergoing a tremendous amount of stress during the Donald Trump Era.

I refuse to let my friendships be torn asunder by political differences. I hope they think of me in the same way.

However, I have heard countless anecdotal stories of how friendships have been ripped apart, flushed away, trampled to death by intense differences. People who hate Trump have lost friendships with those who love Trump. Donald Trump even has infused normally non-political folks with an unusual level of disgust at those who disagree with them politically.

Why has this happened? Is this by design? Is this what Donald Trump envisioned when he rode down that escalator in June 2015 to declare his presidential candidacy? A part of me thinks that Trump actually believed he would produce this bitter divide. I cannot read what passes for this kook’s mind, but my own gut tells me he has produced precisely the political climate he desired.

Trump vowed to “unify” the country. He has talked only to his base, the roughly 40-something percent that has stuck with him since he lost the actual vote to Hillary Clinton in 2016. His refusal to speak to all Americans has created what I believe is this remarkably wide — and widening — divide among American voters.

The greater distance between those who support this guy and those of us who oppose him only has deepened the anger many of us feel toward each other.

Therein, I suggest, is arguably the greatest tragedy of this individual’s tenure as president.