It’s fascinating how, when it suits their purpose, pundits lean heavily on “history” in predicting what they assume will happen.

When the “chattering classes,” as the Brits call them, predicted a Republican takeover of Congress in November 2022, they universally cited “history” as the reason.

The history they cited is that the party of a newly elected president usually loses seats in the following midterm election. Except, of course, when it doesn’t.

There was 1934, when voters doubled down on Franklin Roosevelt’s New Deal, and Democrats picked up 10 Senate seats. Then 2002, when voters rallying behind George W. Bush after the Sept. 11 attacks gave Republicans two crucial Senate seats to regain the majority.

Now there is 2022, when a Republican Party handicapped by Donald Trump gave up one Senate seat — and a majority back to the Democrats.

Why then, as President Biden gives every indication of running for a second term, do so many assume he can’t be serious? We hear about “the top 10 Democratic candidates for 2024.” History suddenly doesn’t matter.

So here’s the history: Since Republicans, with some Democratic support, pushed through the 22^nd Amendment limiting presidents to two terms, no president elected to a regular first term has failed to run for another.

Six have been re-elected: Dwight Eisenhower, Richard Nixon, Ronald Reagan, Bill Clinton, George W. Bush and Barack Obama; four Republicans and two Democrats.

Lyndon Johnson, an “accidental president” succeeding through the assassination of John Kennedy, declined to run for a second term in 1968 amid the national disaster of the Vietnam War.

Finally, three presidents have sought re-election and lost: Jimmy Carter, George H.W. Bush, and Donald Trump. That’s the entire list.

Why then would Biden be the one president with the opportunity to run for re-election, and better-than-average prospects, yet decide not to?

Though history is no longer relevant, “age” is. And while age really is “just a number,” Biden gets no serious examination on that score.

Let’s consider another few pages of history. Before Eisenhower ran for re-election, he had suffered a serious heart attack in 1955 that hospitalized him for seven weeks.

By 1984 Reagan had already shown cognitive impairment, a consideration that weighed heavily by the time of the joint, bipartisan Iran-Contra Committee when it decided not to recommend impeachment.

As committee staffers put it, no one could be sure Reagan understood exactly what he was approving when the U.S. armed its mortal enemies, Iran and the Ayatollah Khomeini, betraying a promise he’d deployed to defeat Carter.

Voters didn’t care about age or disability in 1956 or 1984, giving the two Republicans landslide wins; Reagan’s was the last to date.

Yes, Biden will be 82 next year, but many public figures in the 21st century have delayed retirement.

The 89-year-old Charles Grassley has just been re-elected senator from Iowa. In Maine, Angus King is seeking another term and will be 80 next year; no one seems concerned.

Some, admittedly, wait too long. They would include California’s Sen. Diane Feinstein and, on the U.S. Supreme Court, Ruth Bader Ginsberg.

Serving as president is admittedly different than serving in the Senate, but Biden has done both, as well as being Obama’s vice president.

His stutter is still there, and so is a speaking style not approved by the political elite. Yet he gave the speech of his life at the recent State of the Union, getting Republicans to pledge undying fealty to Social Security — an astonishing feat.

To this admittedly distant eye, the president seems more confident and more assured than ever before. Lagging approval ratings are constantly cited, but what do they mean? In my experience, these ratings have much more to do with external events than any considered assessment of a presidency.

Johnson won a landslide victory in 1964, yet Vietnam killed his presidency. Watergate did a similar number on Nixon after his 1972 landslide.

George W. Bush soared after September 11, then dived as the misbegotten Iraq War turned sour. Even the genial Reagan was pummeled by Iran-Contra, though he recovered.

Assessments of Biden are weighed down by the national tragedy — too little acknowledged — of the coronavirus pandemic, and the inflation that briefly soared thereafter.

But Biden knows things many Democrats have forgotten. Chiefly, that managing the economy — still humming along as inflation subsides — and providing good jobs with robust benefits will always be central to voter preference.

Nothing in life is guaranteed, but a Biden candidacy is a near-certainty, and re-election more probable than not.

So we can continue to produce lists of possible Democratic candidates. Or we can sit back and let history take its course.

Douglas Rooks, a Maine editor, commentator and reporter since 1984, is the author of three books, and is now researching the life and career of a U.S. Chief Justice. He welcomes comment at: drooks@tds.net