It is really hard, anymore, to keep an open mind.

I have tried ever since President Donald Trump took office 15 months ago to keep my mind open to the possibility that the president was not the person almost everyone knew him to be. That includes his supporters, who chose to ignore what he was to vote for who they thought he could become — in the hopes that people can change, leaders can be forged by circumstances and, yes, lightning can strike.

But alas, the jury is in — not the federal jury that could be impaneled if special counsel Robert Mueller doesn’t get fired — and it is evident that Trump will always and forever be Trump, however dangerous that may be to the United States and its democratic institutions.

And the tell-tale sign that we may, as a country, have crossed that line between democracy and authoritarianism-in-the-making was what I witnessed this past week on two occasions following former and fired FBI Director James Comey’s interview with George Stephanopoulos on ABC a week ago.

The first was a discussion with a group of Trump supporters from Charleston County, S.C. Admittedly, the conversation was about Comey, his veracity, reputation and credibility, but the overarching subject matter was their belief that Trump could do no harm and has done no harm, and anyone who suggests otherwise is weak, mean, untruthful and (insert your own adjective). In other words, anything that challenges their own view of the president is, by definition, wrong.

There was not one person in a roomful of voters who could even fathom the idea that it was possible that maybe or perhaps their president could or would do anything wrong in their eyes.

That possibility just did not exist, which means that anyone and everyone who thought differently was not only wrong but un-American and unworthy of any consideration.

Shortly afterwards was an Anderson Cooper interview of U.S. Congressman James Jordan of Ohio. His district is often described as the reddest of the red, which means his allegiance is not to the United States but to that relative handful of voters in his district who see only the red and white in our flag. There is no blue!

That interview devolved into a series of the same questions from Cooper asking as politely and respectfully as he could whether Jordan would concede that our president has lied. Not the 2,000-plus times he lied in his first year in office — a fact confirmed by The Washington Post — but just once. Did President Trump ever lie? To which Jordan answered over and over again, “no.”

Trump didn’t lie when he accused Ted Cruz’s father of being involved in the JFK assassination. Not when he told the world he was going to build a wall and guess who was going to pay for it (by the way, it is no longer Mexico at $12 billion, it is the taxpayers of the United States at $25 billion). And not when he told some supporters that it wasn’t even him on the “Access Hollywood” tapes. Not when he claimed 6 million illegal immigrants voted in the election (didn’t happen), and not when he claimed to have the largest inauguration crowd in history (that didn’t happen either). And not, just this past week, when he changed the narrative of the Comey firing from his national television proclamation that it was this “Russia thing” to now, who knows what!

No, no, no. Congressman Jordan has never heard nor does he have any idea that Trump lies.

It is not me who needs to have an open mind in discussing these matters.

It is the die-hard Trump supporters who, in the face of uncontroverted truth to the contrary at all levels and about all manner of presidential skullduggery, refuse to open their eyes, their ears or their once-present common sense to even acknowledge that the superhuman Trump is really quite human indeed. That is, if lying as a matter of course is a human trait.

So where does that leave us?

Most Americans have a reaction to James Comey’s story about why and how he acted during the 2016 election. It is fair to say that people all around the political spectrum believe Comey tipped the scales in a way that was unprecedented. But few will go so far as to believe that Comey acted in a malicious, treacherous or even treasonous way as director of the FBI. And fewer still will believe that the FBI itself was in on the misadventure.

But not those folks in Charleston County, S.C., and not Rep. James Jordan and his cronies who have never heard Trump lie or seen him do anything wrong. They are the true believers.

It is the true believers in history who have taken their own countries down to defeat. And it will be the true believers in America, aided and abetted by the indifference of an unknowing or uncaring electorate, who could do the same thing to the greatest democracy on Earth.

Our challenge is to convince the Jordans and the Charleston County Republicans in this country to open their minds — if only to let in a little light — before our democracy grows too dark for us to find our way out.

Brian Greenspun is editor, publisher and owner of the Sun.