WASHINGTON • The House select committee on Jan. 6 has failed to dampen support among Republican voters for Donald Trump. Fifty-three percent of Republicans say they would support Trump if he ran again in 2024. They believe that he was a great president and that he was treated unfairly by the media and the political establishment, which tried to delegitimize and destroy him with false accusations of collusion with Russia.

Many accept Trump’s claims that the 2020 election was stolen. No bombshell revelations from the Jan. 6 committee will dissuade them from supporting him.

But is there an argument that might persuade Republican primary voters to nominate someone else? Here is one that could do so: If Trump wins, he can serve for only four years — whereas any other Republican could serve for eight.

Whenever a new president is elected, his supporters anticipate the start of an eightyear presidency. There is a good reason for that. Though presidents are elected to four-year terms, most of those who took office over the past three decades ended up serving for eight. The three presidents who preceded Trump — Bill Clinton, George W. Bush and Barack Obama — each served two full terms. (And before that, George H.W. Bush was arguably elected to serve a third Reagan term.)

But if Trump were to win back the White House, he would be limited to four years — making him a lame duck from his first day in office. Ask yourself: Why does President Biden, who is obviously struggling under the burdens of his office, get irked when Democrats suggest he not run for reelection?

Because without the prospect of a second term, his presidency would be hobbled. The second Biden were to declare he was not running, the jockeying to replace him would begin, and his ability to get his agenda through would be compromised. Even if Biden does not end up seeking reelection, he needs to keep up the appearance that he might.

But Trump could not do that. Why would Republicans nominate someone who is constitutionally barred from seeking another term? A four-year presidency would cede a major advantage to the left in 2028. The power of incumbency is enormous. In the past 12 presidential elections with incumbent candidates, incumbents won eight times, while just four — Gerald Ford, Jimmy Carter, George H.W. Bush and Trump — lost.

Part of the reason is that while a presidential candidate can only make promises, a sitting president controls the levers of power — and thus has the ability to deliver concrete results for key constituencies. The president commands an unparalleled bully pulpit.

He has won the office once so he has a presumption of victory. Barring some catastrophe (or, in Biden’s case, serial catastrophes), the election is his to lose.

It makes no sense to cede those advantages and let Democrats contest an open seat they are much more likely to win after just four years.

Besides, it will take more than four years to dig our country out of the mess Biden has created. The next Republican president will have to tamp down the worst inflation in four decades, the worst crime wave since the 1990s and the worst border crisis in American history. He — or she — will have to restore U.S. energy independence, our economic vitality and our credibility on the world stage.

Any one of these would be an enormous challenge in a single term; but achieving them all in four years would be all but impossible. It’s at least an eight-year job.

If Democrats take back the presidency after four years, they could easily undo progress the next Republican president makes in his or her first term — just like they wiped out so much of Trump’s progress in a matter of months. The United States simply cannot afford that.

Attacking Trump’s character won’t move Republican voters. But a Republican challenger can credibly say: I love Donald Trump. He was a great president. I agree with his agenda. We’ll both bring you the same policies.

The difference is: He can deliver them for only one term, and I can do it for two. Why would we risk handing the White House back to Democrats four years from now, when we can hold it for eight?

MARC THIESSEN