The next time President Trump gets the urge to tweet out his troubles, here’s a friendly suggestion: He could take the first lady down to the Bijoux theater and catch the movie “Darkest Hour.”

It’s the new telling of Winston Churchill’s decision to reject the counsel of the appeasers. They wanted him to cut a deal with Hitler while Britain’s army was trapped on the beaches at Dunkirk in France.

It’s hard to imagine a movie more likely to lift the spirits of the current president. He is, after all, also under pressure to treat with his country’s foes, this time in places like North Korea and Iran (even if we’re not in an active war with them as Britain was with Germany).

The Battle of Dunkirk, in May 1940, put Britain’s new prime minister in a dark depression. He rallied, though, turning the tide with one of the greatest speeches in history.

“Darkest Hour” is the second Dunkirk drama this year. The first was Christopher Nolan’s epic “Dunkirk,” which unfolds on the beaches whence more than 300,000 British and allied soldiers were rescued.

“Dunkirk” was widely criticized for failing to deal with the Nazis by name or capture Churchill’s heroism. “Darkest Hour” repairs that oversight — in spades — and adds dollops of schmaltz.

So naturally, I loved it.

The film opens with Prime Minister Neville Chamberlain, who had appeased Hitler at Munich, barely surviving a confidence vote in Parliament, his credibility as war leader shot. With the Nazis on the march, Churchill is summoned by King George VI.

The king mutters about how Churchill lacks judgment and favors the gold standard. But Churchill had been right about Hitler, and the king asks him to form a wartime government.

Churchill promptly realizes that Britain is on the brink of losing her entire army at Dunkirk. He immediately orders an attack by 4,000 nearby British troops on vastly superior German forces.

Then he orders the famous rescue, in which an armada of civilian boats, the largest ever assembled, is sent across the Channel to pluck the plucky Tommies from under Hitler’s fangs.

Churchill has to organize this while foiling a plot in his own government to get him to sue for peace with Hitler. This conniving is led by the notorious foreign minister Viscount Halifax.

Halifax is a veritable John Kerry. As Kerry later did with Vietnam and Iran, Halifax seeks to avoid a military fight by cutting with Nazis a deal the enemy is sure, at some point, to betray.

Churchill is buoyed by his wife, Clementine. And also by his secretary, Elizabeth Layton, who, at his residences and in the war rooms, works with the prime minister in close quarters.

The prime minister is no Harvey Weinstein. Churchill calls out a warning when he’s about to emerge from the shower in a “state of nature” (Layton demurely dashes into a stairwell).

My typewriter keys would jam up were I to suggest that Trump is on a par with Churchill. Yet there are similarities. Churchill, warns one foe in the film, “stands for one thing and one thing only, himself.”

Like Trump, Churchill has delusions of grandeur, doesn’t play well with others, is bombastic and turns abusive with staff. His domineering personality, though, helps rally Britain in its darkest hour.

It’s George VI who rides to Churchill’s rescue, having figured out that the scoundrel is Halifax. The king shows up at Churchill’s residence to declare his support should the premier stand and fight.

It is, too, the king who urges Churchill to go to the people for advice. Churchill does this by going to Pennsylvania and Ohio . . . pardon, by bolting from his limousine and ducking into the London subway.

The subway scene — in which London commuters tell Churchill to never give up — is fictional. The sentiments of the British people are not. Churchill gets similar support from his outer Cabinet.

So in Parliament he proclaims his immortal vow: “We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills — we shall never surrender.”

“What just happened?” someone asks as the parliament erupts in patriotic cheers.

“He mobilized the English language,” comes the reply, “and sent it into battle.”

In other words, he made Britain great again.

This column first appeared in the New York Post.