Bad day for the infant-jail party. Good day for the third-trimester-abortion party.

Bloomberg’s been weighing a run for president for at least 10 years but he keeps running into the same problem. He can’t get nominated by either side and if he runs as an independent he could end up pulling more votes from the Democrat than the Republican, producing his least favored outcome on election night. With today’s news he seems to have found an outlet for his ambitions: Shower congressional Democrats with cash in hopes of dealing a heavy blow to Trump and, by extension, right-wing populism. It won’t bring him (much) personal glory but if he can convince the GOP that Trumpism is an electoral loser against anyone not named “Hillary Clinton,” there’ll be more space for his brand of centrist politics in the future.

Spoiler: Even if the Dems do win big, it will not convince the GOP that Trumpism is an electoral loser. At the barest minimum, it’ll take a midterm wipeout and a Trump loss in 2020 to make populists consider that possibility. Bloomberg’s going to try to make the first step happen, though.

The new alliance between Mr. Bloomberg, 76, and congressional Democrats marks a fresh stage in the former mayor’s political evolution. After moving freely between elite circles in both parties for years, Mr. Bloomberg is now poised to become one of the Democrats’ most important benefactors: His spending on House campaigns appears likely to exceed the involvement of donors like Sheldon Adelson, the Republican casino billionaire who recently donated $30 million to a “super PAC” aligned with Speaker Paul D. Ryan, and Tom Steyer, the liberal hedge-fund investor spending tens of millions of dollars on voter-turnout programs and television ads demanding Mr. Trump’s impeachment…

In a sign of Mr. Bloomberg’s deep alienation from the Republican Party, he has recently told associates that if he were to run for president in 2020, he would likely do so as a Democrat, according to people who have spoken with him directly.

Oh good lord. He’ll be 78 in 2020, saddled with baggage as a former Republican, a Wall Street titan, and a proponent of “stop and frisk” as mayor of New York. He’ll be facing a field that may be larger than the 16-candidate traveling circus of the GOP primaries two years ago. He has zero chance of being nominated by a Bernie-fying party even if he delivers the House to Democrats on a silver platter this fall. The most he could hope for would be to act as a stalking horse for some more viable contender who may face an unexpected threat from billionaire impeachment maven Tom Steyer. If Steyer emerges as a political force in the primaries, Bloomberg might end up helping establishment Democrats out by serving as a foil for him, a sort of billionaire-versus-billionaire heat shield for stronger candidates. Despite his anti-Trumpism, Bloomberg went out of his way to point out in the statement he issued today that he opposes impeachment — Steyer’s pet issue — saying of those who want to make November a referendum on the subject that “nothing could be more irresponsible.”

He said some other things too:

Republicans, who control both houses of Congress, have done little to reach across the aisle to craft bipartisan solutions — not only on guns and climate change, but also on jobs, immigration, health care and infrastructure. As a result, Congress has accomplished very little.

In addition, and no less troubling, Congress has essentially stopped acting as a co-equal branch of government, by failing to engage in the kind of oversight of the law that the Constitution requires and the public expects.

In fairness, some Republicans have taken their constitutional and legislative responsibilities seriously, like my friend John McCain. But too many have been absolutely feckless, including — most disappointingly — the House leadership.

Fair point about congressional Republicans rolling over for Trump, although they get no Democratic support even when they try to stand up to him. It’s also certainly true that a Democratic House would be more aggressive in its oversight of the White House than a Republican one is. With Adam Schiff in charge instead of Devin Nunes, the House Intel Committee would be … different. And all of the conflict-of-interest stuff related to POTUS and his family profiting from their new government roles that’s been given short shrift by Republicans would be put front and center by Dems. Having Democrats in charge of the House would mean that instead of getting a daily “witch hunt!” tweet from POTUS about Mueller we’d be getting them six times a day about various investigations being conducted by all sorts of Democrat-led House committees.

Question, though: He says his core concern is electing a majority that’ll reach across the aisle, and his solution to that problem is … Speaker Nancy Pelosi, who passed ObamaCare without a single Republican vote in 2010? What?

Exit question: Any Republican billionaires out there willing and able to match Bloomberg? Sheldon Adelson? Paul Singer? Steve Wynn? (Probably not Steve Wynn.) Don’t say Trump. I mean a real billionaire.