It’s sobriety time for Trump partisans who were feeling wildly upbeat in the wake of the self-destructive Democratic failure with impeachment and from polls showing most Americans expected the president to win a second term.

The primary results Tuesday night in Michigan should be setting off alarm bells in Trump Land. They are so suggestive of a possible Democratic path to victory in November that they remind me of the expert speaking in the midst of a crisis on a TV chat show in the Pixar classic “Monsters, Inc.”

He is a talking pencil who speaks with a Viennese accent as he declares, “It is my professional opinion that now is the time TO PANIC!”

Here’s why. We have been seeing startling levels of turnout in some Democratic primaries and caucuses. In New Hampshire, 300,000 votes were cast for Democratic candidates, a 20 percent jump over 2016 in a state that only went for Hillary Clinton by 2,800 votes.

In South Carolina, there were nearly 530,000 votes cast, an ­astonishing increase of 260,000 over 2016. The Palmetto State won’t go blue for Joe Biden in November. But African-Americans in the state showed up for him in a way they didn’t for Hillary Clinton — and it was Clinton’s inability to generate overwhelming black turnout in 2016 nationally that helped doom her in the Electoral College.

Then, on Tuesday, came Michigan, where more than 1.5 million Democrats turned out in another easy Biden romp over Bernie Sanders. That’s big. In 2016, 1.1 million Democrats voted in the primary. That was about 50 percent of the Democratic turnout in Michigan in November 2016 of 2.2 million.

Consider this: The 2020 primary number constitutes 68 percent of the 2016 election vote — in March. In a primary.

This matters, because if there is one thing we know about politics, it’s that a primary voter is a general-election voter. And Joe Biden just got 240,000 more votes in Michigan than Hillary Clinton received in 2016 — in a state she lost by a mere 10,500.

Remember that then-candidate Donald Trump’s victory in Michigan was the surprise of all surprises on election night in 2016. It gave rise to the idea that Trump had a unique hold on the white working class, because he generated new voters — disgruntled former voters and even former President Barack ­Obama backers among them.

If Democratic enthusiasm ­remains high through November, Biden will easily generate tens of thousands, if not hundreds of thousands, more votes than Hillary Clinton did there.

All this circumstantial evidence suggests Democrats are indeed united — in their desire to end the Trump presidency. Remember the staggering results of the November 2018 midterms, when Democratic candidates ­nationwide secured 40 formerly Republican House seats by garnering 62 million ballots — just 3 million fewer than Hillary Clinton had received in 2016.

Such a thing had never happened before. Past midterms had electorates maybe 40 percent of the size of the presidential-year vote. All Democrats need to do in November 2020 is have an electorate 10 percent larger than the 2018 electorate — say, around 68 million votes — and they will likely win the presidency going away.

The primary turnout numbers suggest Democrats remain passionate and enthusiastic and united in their anti-Trumpery. What’s more, the results from the 20 states that voted over the past 10 days suggest that Democrats feel a lot better about Biden as their 2020 candidate than they ever felt about Hillary Clinton in 2016.

Republicans look at Biden and see a target-rich environment, and he is. But Democrats are ­beginning the race to November with open eyes.

Democratic voters know Biden can’t stop talking. They know his son Hunter is trouble. They know that cognitively, Biden has lost somewhere between a step and the 10,000 steps you need to register a good day on your FitBit.

But they took a hard look at the choices they had — and, as things heated up, the binary choice between Biden and Sanders — and decided with lightning speed they would have a better shot in November going for Lord Gaga over Comrade Bernochkie.

And make no mistake: They are going to do whatever they can to get him over the top.

jpodhoretz@gmail.com