President Donald Trump says he’s not acknowledged as the greatest president in history because people don’t like him. He’s half right.

If another president had achieved what he has — Trump told Corey Lewandowski and David Bossie, authors of the book “Trump’s Enemies: How the Deep State is Undermining the Presidency” — they would say “he’s the greatest president in history, and I blow Ronald Reagan away.”

Trump often compares himself to Reagan, widely considered the greatest of modern Republican presidents. Trump once tweeted that he’s been criticized for his mental state but so was Reagan.

But Trump ignored the sad fact that Reagan’s mental state deteriorated during his presidency because of Alzheimer’s Disease.

Trump once retweeted a photo of him shaking hands with then-President Reagan, which included a quote from Reagan that said: “For the life of me, and I’ll never know how to explain it, when I met that young man I felt like I was the one shaking hands with a president.”

Reagan never said this.

Trump’s tendency to compare himself to Reagan has grown particularly irksome to those who knew Reagan and worked for him.

“Of the many canards that Trump tells, nothing is more galling or untrue than when he or some of his supporters say he is as good a president as — or even better than — Ronald Reagan,” former Reagan speechwriter Craig Shirley and Reagan biographer Mark Weinberg recently wrote on The Hill website. “In what universe?

In other words, we knew Ronald Reagan, we worked for Ronald Reagan — and you, Donald Trump, are no Ronald Reagan.

Shirley and Weinberg said that they are particularly vexed by Trump’s dishonesty. The Hill reported that Trump had made more than 16 thousand false or misleading statements during the first three years of his presidency.

Reagan, by comparison, had his faults, Shirley and Weinberg said, “but he was not a liar.”

Trump compares his popularity to Reagan’s. This is a fair comparison only if you compare their popularity with Republicans. Reagan was also popular among independents and Democrats. Trump isn’t.

People liked Reagan even though they disagreed with his politics. People agree with Trump’s politics, but many still don’t like him.

We could use someone like Reagan in the White House right now — or at least someone like him. Trump is no Reagan.

There was no crisis like the coronavirus in the Reagan presidency, or anything like it, so we don’t know how Reagan would have responded. But there were moments of despair, anguish and fear when the country turned to Reagan and he responded with strength and comforting words.

When a would-be assassin shot Reagan, he did not refer to the seriousness of the wound but joked to doctors, “I hoped you are all Republicans,” and to his wife, “honey, I forgot to duck.”

When the space shuttle Challenger exploded, Reagan uttered the following words: “We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye and ‘slipped the surly bonds of earth’ to ‘touch the face of God. ‘”

How would Trump have responded to the Challenger tragedy. Who would he have blamed?

Reagan saw America far differently than Trump does. Reagan saw America as a unified country and he sought to uphold its beliefs and values.

Trump is a vengeful narcissist. He thinks America is his own family business and he can say whatever he wants and do whatever he wants with impunity.

Reagan, Shirley and Weinberg said, “was far too secure to compare himself to anybody. He eschewed the use of personal pronouns.

He said ‘we,’ ‘us’ and ‘ours,’ not ‘I’ ‘me’ or ‘mine.’ “