Swaths of liberals still swoon over U.S. Sen. Elizabeth Warren like Beliebers at a Justin Bieber concert here in the Bay State, but it turns out she’s not so popular in the other 49. So Democrats better find another superstar if they want to take back the White House in 2020.

In a Politico/Morning Consult poll released yesterday, any unnamed Democrat beats President Trump in a 2020 presidential matchup. A dust mop with a “Democrat” sign on it beats Trump. But the Senate’s liberal darling doesn’t. Trump, despite his own series of stumbles, still beats Warren — one of the Democrats’ most prominent national faces — 42-36.

Democrats have received their warning notice. Don’t let this woman, a self-appointed leader of the so-called Resistance, be the face of your party.

Perhaps voters were turned off by Warren’s unhinged Twitter tirades against Trump during the presidential campaign. Or her more recent partisan obstructionism against our new president. But what could’ve been the last straw is Warren’s insatiable grandstanding at Cabinet hearings. Warren causes a spectacle at hearings, then raises campaign funds off it.

Here’s how the game works: Mouth off at high-profile meetings with the cameras rolling, grab headlines, then siphon millions out of unsuspecting Democrats’ wallets.

The losers: Massachusetts voters who elected Warren in 2012 to better their lives. Ultimately she’s just bettered her own.

It’s no wonder thousands of Massachusetts Democrats switched party affiliation in the presidential primary to vote for Donald Trump. Voters are waking up.

Trump appeals to blue-collar union workers who will benefit from his pro-jobs agenda. He wants to spend more than a trillion dollars on much-needed nationwide infrastructure projects. Working-class Democrats who will get those jobs.

Trump also wants to repeal and replace Obamacare. Winners: Democrats who saw their jobs get cut to part time will now revert back to full-time workers. And adios to that costly union-slamming “Cadillac Tax.”

Energy projects like the Keystone pipeline benefit Democrat union workers. Here’s what is certain: If Dems don’t wake up to the fact that their core constituency — blue-collar workers — are flooding to the GOP thanks to greater economic opportunities with a Republican administration, liberals will have no one to blame but themselves for another crushing defeat in 2020.

Knowing that voters care about jobs and the economy — more than “safe spaces” and transgender bathrooms — it’s no wonder Warren loses in a matchup against Donald Trump. He’s a jobs creator, she’s not.

The warning to Dems is clear: Find another party leader or get fired again in 3 1⁄2 years.

Adriana Cohen is host of the “Adriana Cohen Show” airing Wednesdays at noon. Follow her on Twitter @AdrianaCohen16.