I already have declared my belief that Robert Francis “Beto” O’Rourke shouldn’t run for president of the United States in 2020. My belief is that he doesn’t yet have the seasoning or the experience to take on such a monstrous responsibility.

But then . . .

A thought occurs to me.

Another American politician lost a bitter campaign to the U.S. Senate and two years later he, too, was elected president.

Abraham Lincoln, anyone?

Lincoln ran for the Senate from Illinois, but lost to Stephen A. Douglas in 1858. The failed Senate candidate already had served in the U.S. House, but decided to push for higher office.

Having lost that bid, Lincoln licked his wounds — and then decided to go for an even bigger prize in 1860. That year he was elected president, but after he was nominated by the Republican National Convention on the third ballot. It was a struggle to win the party nomination. Lincoln’s presidency would prove to be the ultimate trial by fire, with the nation ripped apart by the Civil War.

OK, let’s hit the fast-forward button for a moment.

Does this sound like a scenario that Beto O’Rourke might follow were he to declare his own presidential candidacy? Democratic party activists and big-money donors say they want him to consider it. They like the young man’s energy and the passion he infuses into his supporters. He damn near beat Republican Sen. Ted Cruz in heavily Republican Texas earlier this month and that has Democrats all agog over his future.

The Washington Post reports that O’Rourke’s near-success in Texas has turned the Democratic primary outlook into a chaotic mess.

O’Rourke, who’s finishing his term as a congressman from El Paso, will enter private life and just might consider whether to make the plunge yet again, only reaching for the very top rung on the ladder.

Or . . . he might decide to take on Texas’s senior U.S. senator, John Cornyn, in 2020.

I remain a bit dubious about O’Rourke’s presidential timbre.

However, I am somewhat heartened to realize that there’s precedent for what the young man might decide to do. If he hears the voice calling him to run for the Big Job, he might do well to look back on Honest Abe’s effort two-plus centuries ago. It might give him the strength to plunge ahead.