This is a lawsuit that seems both like President Trump’s last major attempt to get the courts to overturn his loss — and like it’s destined to flop. That’s the consensus of numerous legal experts on a recently filed lawsuit by Texas Attorney General Ken Paxton (R) alleging rampant fraud in four states that numerous other court cases have so far failed to prove.

Paxton alleges “the 2020 election suffered from significant and unconstitutional irregularities” in four states that swung from President Trump in 2016 to President-elect Joe Biden in 2020: Pennsylvania, Wisconsin, Michigan and Georgia.

And he asks the Supreme Court to allow state legislatures to pick electors in those states instead. That part of the equation is now familiar, given Trump is also trying to pressure state lawmakers to overturn election results.

The Washington Post reports that Trump has become enamored with the suit. He, through a personal lawyer rather than the administration, has joined in. He talks to his advisers about it; he’s tweeted about it. Republican attorneys general from 17 other states have already joined in.

Not all Republicans, however, are on board. Sen Ben Sasse (R-Neb.), an occasional Trump critic, singled out Paxton’s own legal troubles back home and said this, in part, in a statement about the lawsuit: “It looks like a fella begging for a pardon filed a PR stunt.” (Paxton is facing indictment on securities fraud charges and says he has not discussed a pardon with the White House).

But more than 100 House Republicans signed on to a brief supporting the effort.

All these Republicans are setting themselves up for a quick failure, legal experts who have spoken to The Fix and other Post reporters say.

It’s a legitimate question what right Texas even has to bring such a lawsuit against other states. (Lawsuits between states are rare.) The Supreme Court could dismiss it out of hand for that reason, if it offers a reason at all.

And then you get into the substance of it, which is more like a Newsmax reel than actual legal arguments, said Jessica Levinson, a law professor at Loyola Law School and host of the legal podcast “Passing Judgment.”

“It’s all of the Hail Mary pass lawsuits strung together, in the erroneous hope that somehow lining them all up will make them look more impressive,” she said. “It’s procedurally defective. It’s substantially defective. And I think the Supreme Court will have not only no appetite for it, but it will actively nauseate them.”

Given the court this week already quickly threw out another lawsuit to overturn results in Pennsylvania, it’s more likely than not that the court will do the same here, even with three Trump appointees on the court.

Here are the most spectacular allegations in the lawsuit, which could be Trump’s last chance to try to use the courts to turn his loss into a win.

The allegation: These states expanded absentee ballot use in a pandemic

Paxton argues that it was unconstitutional for state election officials, like secretaries of state, to expand mail voting, because the legislatures get to decide how to run elections. Despite there being no evidence that mail-voting leads to statistically significant fraud, he says that these states changed or modified their rules to allow more voting by mail due to the pandemic opened the door to fraud. And he uses hyperbole to make his point: “Absentee and mail-in voting are the primary opportunities for unlawful ballots to be cast,” he says, alleging that “created a massive opportunity for fraud.” (It’s true that in voting by mail, the ballot is filled out in private, which opens up more potential avenues for fraud. There’s just no evidence it actually happens. But well before 2020, five states conducted their elections by mail for years, with no evidence there was large-scale fraud.)

Paxton ignores that Wisconsin and Michigan already had programs set up to vote by mail before the pandemic. Wisconsin has allowed people to vote absentee without an excuse since 2000.

The allegation: These states enforced their rules about where poll workers could watch counting

Paxton strings together half a dozen examples he says demonstrate “rampant lawlessness” in the vote-counting process: poll workers not allowed to watch ballot counting (because election officials had said they were violating covid-19 restrictions); “suitcases full of ballots being pulled out from underneath tables after poll watchers were told to leave”; and he dips his toe into the conspiracy theory that Dominion voting machines might not have worked as they were supposed to.

Much of that evidence has been reviewed and thrown out by various courts. And even if some poll workers were asked to leave, does that mean tens of thousands of votes for Trump were counted for Biden? In Pennsylvania, Trump’s lawyers were forced to admit they did have poll workers in the room watching counted ballots, even as they tried to file a lawsuit arguing the opposite.

The allegation: That states counted votes as they came in

Paxton pulls an accusation straight out of Trump’s Twitter feed — not even something Trump’s lawyers dared make in a courtroom — that it was odd that Biden took late-night leads in states after Trump initially was leading.

We’ve explained this. Trump’s voters, following his own lead, largely voted in person. In-person votes are quicker for officials to count than mailed ballots. Biden’s voters largely voted by mail. Those take more time to tally. So as election officials worked throughout the night, they started adding the mailed votes to the vote count in their states. Paxton is literally arguing that the Supreme Court overturn an election because states counted their votes. (In a separate part of the lawsuit, he even acknowledges the partisan difference in how people voted: “Democrat voters voted by mail at two to three times the rate of Republicans.”)

The allegation: That Biden did better in 2020 than Hillary Clinton did in 2016 in these states

Paxton alleges that “the statistical improbability of Mr. Biden winning the popular vote in these four states collectively is 1 in 1,000,000,000,000,000.” It’s unclear, even in the lawsuit, where and how he got that number, says The Post’s Philip Bump.

And we’ve been over the “How could Biden have done better than Clinton?” claim, too. It’s a derivative of the argument that Biden didn’t perform well compared to Hillary Clinton in cities except for four big ones in states he happened to win — Atlanta, Detroit, Milwaukee and Philadelphia.

The Fix’s Aaron Blake calls this allegation “the epitome of bad faith, poor research and our inability to rid our political discourse of a patent falsehood.”

Biden did get more votes than Clinton in many metro areas. And he actually did worse than Clinton in Philadelphia.

Biden won these four swing states not by massive fraud, but by learning the lessons from Clinton’s 2016 campaign and not being overconfident about polling showing him doing well in these states. He campaigned successfully to take away Trump’s support particularly in suburban areas.

Bottom line: Biden got more votes where he needed to win the electoral college, just like Trump did in 2016.