SACRAMENTO —  How did we allow a convicted felon, compulsive liar, adjudicated sexual abuser and wannabe dictator to be elected our nation’s president? Three words: Democrats botched it.

It shouldn’t have been even close, running against a man with his disqualifications. And, in fact, it wasn’t. Republican Donald Trump won with ease.

Here’s my post-mortem on the political demise of Democrat Kamala Harris.

Just as Republicans themselves are at fault for allowing the California GOP to sink into irrelevance in state government — through years of bad positioning and ignoring moderate voters — top Democrats fumbled nationally leading up to the 2024 presidential election.

It started with a betrayal by President Obama in 2016. The blame begins with him.

Obama reportedly shoved aside his own vice president, Joe Biden, and backed Hillary Clinton for president. He dissuaded Biden from running.

Democrats thus missed their grand opportunity. Biden was at his peak back then and probably would have beaten Trump, nipping his political career in the bud.

Why’d Obama do that? We can only guess. But here’s my assumption:

In 2008, after Obama had beaten Clinton in a bitter race for the party’s nomination, he was desperate for her unifying support. They met face-to-face at California Sen. Dianne Feinstein’s home in Washington, D.C. I don’t know the precise deal they cut. But after his election, Obama gave Clinton the coveted secretary of state post and eight years later backed her for president over Biden.

Clinton turned out to be a poor candidate.

Many Democrats believed she lost because America wasn’t ready for a female president. But as New York Times columnist Maureen Dowd wrote recently:

“Hillary Clinton did not lose because she was a woman. She lost because she was Hillary Clinton. She didn’t campaign hard enough, skipping Wisconsin and barely visiting Michigan. She got discombobulated about gender …”

So Trump was elected president the first time.

Then in 2020, Biden finally won the Democratic nomination but, in my view, fumbled his choice for running mate. He had pledged to name a female veep and was under heavy pressure to choose a woman of color.

Look, it’s a mistake to lock yourself into a narrow field of potential selectees months before needing to make a decision.

And maybe it’s time for Democrats to ease up on identity politics. Whatever the policy merits are, it doesn’t appear to be benefiting Democrats politically.

Anyway, Biden’s preferred woman of color for vice president was Harris, the then-California senator whose own White House bid had bombed. She bowed out before any primary votes were cast, avoiding an embarrassing loss in her home state.

Biden was largely drawn to Harris because she and his late son, Beau, were close allies when both were state attorneys general.

He probably would have been better off tapping then-U.S. Rep. Karen Bass of Los Angeles, chair of the Congressional Black Caucus, who was likable, energetic and a goal-achiever. Bass later was elected L.A. mayor.

But the Biden-Harris ticket ousted Trump from the White House, with the scheming poor loser refusing to concede defeat and inciting a riotous mob at the nation’s Capitol in a failed effort to block certification of the election results.

As vice president, Harris eventually became less popular even than the fading Biden, according to polls, and was generally regarded as a drag on the president’s 2024 reelection prospects.

By far the biggest drag, however, was the 81-year-old Biden himself. And he shares significant blame for Harris’ loss last week. That’s because he reneged on his 2020 campaign promise to be a transitional president and pass the torch to a younger generation.

He stubbornly refused to face reality and listen to Democratic voters who kept telling pollsters they desired a spryer candidate. It was only after Biden exhibited the worst TV debate performance in history that he bowed to party pressure in July and stepped aside.

But I also blame Democratic congressional leaders and large party donors for not leveling with the president much earlier and giving him a shove.

Biden’s attempt to seek reelection kept Democrats from conducting a normal, competitive nominating process that is vital for any party standard bearer. It hones battle skills, tests voter messages and builds a national support base.

Harris may have been the voters’ choice in primaries. We’ll never know. She captured the nomination by default — without ever having won a single vote in a caucus or primary. There wasn’t even a convention fight because other Democratic wannabes didn’t have the stomach to contest her.

Harris actually turned out to be a fairly good candidate, exceeding many people’s expectations, including mine. She clobbered Trump in their sole debate.

But it didn’t matter much. Voters sought change and she represented the status quo.

She failed to adequately respond to working class voters’ major concerns about the economy and illegal immigration.

She overemphasized abortion rights, a winning issue for Democrats in the 2022 midterm elections that had played out by last week.

And voters didn’t want to hear about Trump being a scumbag. They already knew that and didn’t really care. A majority no longer have a standard of decency for a presidential candidate — or if they do, it’s lower than a rattlesnake.

Mothers can still tell their children that in America anyone can grow up to be president. And now they can add that it’s true even if they lie, cheat and incite a deadly insurrection against the nation’s government.

Just don’t be a California Democrat.