ANALYSIS — Both parties have a lot at stake in the midterms, but it’s the Democrats for whom Tuesday’s elections are do or die.

With the president’s job approval numbers weak and a majority of likely voters telling pollsters they would prefer a Democratic Congress, Democrats simply cannot afford to fall short of taking back the House on Tuesday.

A loss would be both gut-wrenching and deflating. With their large financial advantage and strong class of challengers and open-seat recruits, Democrats seem poised to take at least 30 House seats from the GOP, quite possibly more.

President Donald Trump, on the other hand, sounds increasingly desperate in his calls to end “birthright citizenship” and his decision to send thousands of U.S. troops to the border.

Women, minorities and the young (voters ages 18-29) appear energized, intent on voting Democratic to send a message to the White House and the GOP.

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The apparent shift of white, college-educated women, especially in the suburbs, away from the Republicans and toward the Democrats seems to have fundamentally changed the arithmetic of American politics, at least for 2018.

The president comes off as so mean-spirited, vulgar and mendacious that a Republican victory in the House elections would suggest that most voters don’t really care about Trump’s fearmongering and lying.

That would certainly deflate the president’s critics, who are convinced he has gone too far in his first two years in the White House.

What happened?

If the Democrats don’t take back the House, what excuses would they have? They’d point to gerrymandered districts and the nasty campaign ads run by Republicans.

They’d point to Trump’s misstatements and dog whistles.

They surely would point to the healthy economy.

But they would also have to acknowledge that all of Trump’s outrageous comments and behavior did not cause enough Americans to send a loud and clear message of dissatisfaction about the first two years of his presidency — and that would be depressing.

Moreover, if Republicans retain their House and Senate majorities, possibly even adding an additional Senate seat or two, the president would see that outcome as a ratification of his agenda and style.

His already abundant self-confidence would be stoked, leading him to believe that he can do and say almost anything.

There would be more mocking of adversaries, more belittling of opponents and more warnings about invaders, illegal immigrants, violent criminals and the lying media.

And there would be more attempts to undermine institutions, both in government and outside, that seek to check his authority.

No fatal loss

Unlike the Democrats, Trump and his Republican acolytes could survive the loss of the House because they would easily come up with a litany of excuses that would play well with supporters and sympathetic media.

Trump would complain that Republican candidates didn’t embrace him strongly, that the national media lied about him and ignored the success of his first two years, that George Soros and Michael Bloomberg helped Democrats buy the election, and that he did better than other presidents have in the midterms, which are always difficult for the occupant of the Oval Office.

He might even claim that millions of illegal immigrants voted.

His supporters would almost certainly applaud and agree.

Moreover, if Republicans keep the Senate, which appears more likely than not, Trump would crow about those successes and argue that he provided the victory margin in many contests.

He’d also argue that the Senate is more important than the House anyway, since the Senate confirms judges and many government appointees.

Trump will have excuses aplenty because he always has excuses. It’s never his fault.

To his supporters, Trump would remain the only person who can stop illegal immigrants from “invading” the United States; China and Europe from ripping us off; and Democrats from imposing socialism on the country.

A Democratic House would give Trump a punching bag for the next two years and another reason for his supporters to stick with him in 2020.

Of course, a Democratic House would also create problems for Trump over the next two years, as could special counsel Robert S. Mueller III.

But Trump enjoys mud wrestling, and would still have all the power and authority of a sitting president while he battles his adversaries and critics.

Losing control of the House would be bad for Trump, who would have to adjust to a new political landscape and worry about his coalition going into 2020. But not winning the House would be a disaster for Democrats, who immediately would have to wonder what it will take to convince the country that Trump is destroying America.