There once was a time when Hillary Rodham Clinton was considered a shoo-in to become the second consecutive history-making president in U.S. history.

You’ll recall the narrative.

She would succeed the first African-American president, Barack Obama, by becoming the first female president. She would win in a historic landslide. No one since, say, 1952, when Republican Dwight Eisenhower — who commanded our troops to victory over Hitler during World War II — was considered as destined to become president.

Then a funny thing happened.

Her critics began making points that stuck. They drew blood. The email tempest. Benghazi. Her occasional waffling. Is she trustworthy?

Then along came Bernie Sanders, the independent U.S. senator from Vermont running as a Democrat. He started drawing those huge crowds. He’s blasting the daylights out of big banks, Wall Street and demanding wage equality. He’s a socialist — and let’s cut the crap about “democratic socialist,” which is meant to soften the “s-word.”

Now the once-inevitable president is less so.

Fellow Democrats are now flocking to New Hampshire to say things like “a loss here won’t doom” the candidate. Former Texas Democratic gubernatorial nominee Wendy Davis is among the latest to recite that mantra.

Maybe it won’t. Then gain, maybe it’ll signal a dramatic replay of 2008, when the then-U.S. senator from New York, Clinton, was supposed to be the nominee — only she ran into that young upstart from Illinois, U.S. Sen. Barack Obama, the self-proclaimed “skinny guy with the funny name.”

Does history repeat itself? Are we witnessing a sort of 2.0 version of what occurred eight years ago?

A lot of political analysts still believe Hillary Clinton is the candidate to beat. She has the so-called “ground game” in Iowa, New Hampshire and South Carolina. She’s got the party machine lubed and ready to roll for her in other key primary states.

Let’s remember, though, this truth about the 2016 campaign. All the “conventional wisdom” has been tossed into the Dumpster. I’m one of those who believed Clinton was marching straight to the Oval Office. I didn’t foresee what would transpire . . . any more than I foresaw would be happening on the Republican Party side of this contest.

You want unpredictability in a presidential campaign?

I believe we’ve gotten it.