Not long ago I wrote about the lessons to be learned from the demise of the Roman Republic. I don’t really blame Americans for being unfamiliar with this tragedy. It happened a very long time ago. Moreover, few of us were taught about it in school.

Recent events, however, are another matter. We should be able to recall episodes that occurred mere decades ago. Young people have an excuse. They were not around when they took place. But older folks — the generation now making important decisions — have no such alibi.

Refusing to learn from history is a fool’s errand. It is a prescription for making the same mistakes three, four or 27 times in a row. If we are to use our brains, we must begin by understanding incidents that happened within our lifetimes.

I am talking about the Reagan presidency and the light it shines on the Trump administration. By most accounts, Reagan had a successful presidency. He tamed inflation, ignited the economy and brought the Soviet Union to its knees. What most “experts” said couldn’t be done, he did.

What we forget was the constant sniping he was under. Reagan was considered an empty-headed clown by most of the people who criticized his policies. They regarded him as an actor who had no business being in the oval office. Since they knew better than he did, it was his responsibility to listen to them.

This included his condemnation of the Soviet Union as an evil empire. Didn’t he understand that pulling the bears tail was a formula for war? In an era of atomic weapons, only a madman or ignoramus would make such a mistake. The appropriate course was to placate the commissars.

Similar logic applied to star wars. Proposing to build a rocket-operated shield against Russian missiles was equally unwise. Because this project was technically unfeasible, it wasted money that could better be spent elsewhere. The president clearly needed an education in reality.

Except that the Soviets took Reagan seriously. They feared they could not keep up with America’s technological advances and therefore sought an accommodation. This, as later events revealed, laid the foundation for the collapse of the Soviet Union.

Fast forward to today. Donald Trump is even more disrespected. His policy of using targeted tariffs against nations that flout our interests is also dismissed as a fool’s errand. Trump obviously doesn’t understand the virtues of free trade or he would never behave so recklessly.

As his detractors see it, Trump is either crazy or dumb. His economic insights are so lacking in depth that he doesn’t realize that a tariff is a tax. Were he a tad more sophisticated, he would appreciate that tariff wars hurt American’s more than those at whom they are aimed. In short, they do not work.

Only in the case of Mexico, they just did. Even many Republicans were saying that threatening our southern neighbor was imprudent. While its leaders would never comply with demands to slow the illegal immigrant traffic, in the meantime American consumers would get hurt.

Nevertheless, Trump was right and they were wrong. But don’t hold your breath waiting for an apology. There will be none — anymore than there was one with Reagan. The know-it-alls, who are among the most vocal critics, learn the least from history. They are ideologues as opposed to genuine experts.

Here is a secret that Trump’s detractors don’t understand. If you want to win a fight, you must be aggressive. You have to take calculated risks or you are facilitating the victory of your opponent. Once the other side realizes that you are playing for a draw, they know they have an opportunity to win.

Winners realize that they can get hurt in an all-out brawl. They are also aware that they have limitations. Happily, they are likewise mindful that their adversaries have limitations. Hence instead of concentrating on their own weaknesses, they seek out the weaknesses of their opponents and exploit these.

Reagan understood this, and so does Trump. If those who hate these men had more awareness of history, they would realize that this is a nearly universal truism. Cortez would never have conquered the Aztecs had he not grasped this fact. The same was the case when Genghis Khan attacked China.

History can be fascinating — and surprising. Far from being the irrelevancy many contemporaries make it out to be, it can help us avoid a slew of errors. Trump may not be a student of history, but the choices he makes often align with it.

Melvyn L. Fein, Ph.D., is a professor

emeritus of sociology at

Kennesaw State University.