New York’s establishment Democrats got eaten alive Tuesday night — and they did it to themselves.

Worse, the national party has the same problem.

Heck, Brooklyn’s Sen. Chuck Schumer and Rep. Hakeem Jeffries, the top two Dems in Congress, just got humiliated in their own backyard — and radical candidates across the country are declaring they’ll demand new House and Senate leaders once they win.

The socialists have another big chance in Los Angeles, where Nithya Raman could well win this fall’s runoff against the utterly awful Mayor Karen Bass after the establishment-built open-primary rules shut down Spencer Pratt’s challenge.

Other “moderates” across the nation may go along with the Democratic Socialists just to stay off the hit list: That’s what Gov. Kathy Hochul has done by appeasing Mayor Zohran Mamdani.

He kept up his end of the bargain by not backing a lefty primary challenge to the gov — but he’s now greatly upped the DSA’s power in Albany with victories in legislative races to match Tuesday’s sweep of three House contests.

Hochul has been telling moderate Dems she can hold back the socialists; she’s now betrayed them — a damning repeat of Andrew Cuomo’s years as gov.

All the establishment losers figured they had it easy in safe Democratic seats: Just keep up the Orange Man Bad schtick; continue burning taxpayer money to feed your nonprofit and union allies; never call out the absolute lunacy pushed by the far left.

Heck, echo that idiocy: It wins you primary votes, right? In blue America, that’s all you really need.

Except that refusing to stand up to the crazies normalizes the madness, leaving voters no clear reason to stick with you when the extremists say it more convincingly.

Party machines were also fine with the steady drop in turnout for primaries: It made it easier for the handful of insiders (and their special-interest allies) to fend off challengers . . . until the hard left joined the fight with its own machine.

Having let its own turnout operation and neighborhood roots decay, the establishment couldn’t even manage to motivate non-fanatic voters to turn out Tuesday to stave off the Marxist Wave.

It got fat, then got eaten.

The Biden years should have been a warning against where “we can work with these people” leads.

The party chose Joe as its 2020 standard-bearer to stop the Bernie Sanders steamroller, but the new prez felt compelled to let the hard left drive on race, “gender,” crime, the border and everything else — opening up the door for President Donald Trump’s return.

Another problem with the Democratic establishment’s “buy everyone off” approach is that it eats the seed corn — that is, it ruins the economy and living standards in blue states, driving the most productive people away.

California, New York, Illinois: They’re all now bleeding House seats and taxpayers — and not just the fat cats.

The hacks in Albany and Sacramento may feel safe, but the loss of national power is already starting to reduce federal largesse: What are they going to do when Washington stops letting them milk hundreds of billions from the national fisc to fund their insane spending?

Yes, the Republicans need to get their own act together, in blue states and nationally — but that gets easier to do when extremists keep taking over the Democratic Party.

Then again, many Dems now argue that they need to permanently lock in their DC power when next they win the White House and Congress, by packing the Supreme Court and rewriting national voting laws as they have so many states’.

That is, establishment Democrats still aren’t facing the threat from the left: They may lock out the Republicans only to have the DSAers throw them into the desert, too.