Three years ago Saturday, the central part of the ObamaCare law took effect. But the odds are now overwhelming that President Obama’s signature achievement won’t make it to its fourth birthday.

Take it from Bill Clinton.

It’s “the craziest thing in the world,” the ex-prez told a Michigan rally for wife Hillary on Monday. “The people who are out there busting it, sometimes 60 hours a week, wind up with their premiums doubled and their coverage cut in half.”

Moreover, he noted, “the people getting killed in this are the small-business people and individuals who make just a little bit too much to get any of these subsidies.”

In short: “It doesn’t make any sense.”

All true — and what we and other critics of the misnamed Affordable Care Act have been saying since the bill was introduced.

Even Obama now admits his health care law has “real problems” (though his fix is, surprise, even more taxpayer subsidies). And the New York Times this week reported the “emerging truth” that ObamaCare “will certainly have to change to survive.”

Donald Trump and most Republicans want to replace the whole law. But Hillary Clinton and other Dems want to double down — by moving toward a “public option,” i.e., insurance direct from Uncle Sam, eliminating the last vestiges of competition and further minimizing consumer choice.

As it stands, private insurers, facing millions in losses, are pulling out of the ObamaCare exchanges in state after state: The federal rules add up to (as Bill put it) an “insurance model” that just “doesn’t work.”

Health Republic of New Jersey pulled out this week after more than $59 million in losses, leaving just two companies on the Garden State’s health care exchange.

Yes, the law boosted coverage — by spending tens of billions to goose Medicaid enrollment. It’s been a wash when it comes to private coverage.

Even as millions found that, no, you can’t keep your doctor or your old plan. And you’re probably paying more to get less.

Millennials — whose premiums are supposed to subsidize plans for older Americans — aren’t signing up. So prices keep rising, and more wheels keep coming off.

And the voters know it. That’s surely why Bill opted to tell the truth in Michigan — even though it was sure to infuriate Obama.

Which suggests to us that Bill Clinton, the most gifted politician of the last generation, thinks Hillary’s campaign is in deeper trouble than the polls are showing.