Sen. Bernie Sanders, I-Vt., was against socializing the U.S. health care system before he was for it. Who knew?

In the late 1980s, Sanders, who at the time was the mayor of Burlington, Vermont, acknowledged that a Canadian-style government-run health care system “would bankrupt the nation.”

But that was then, and this is now.

With considerable fanfare, Sanders on Sept. 13 unveiled the outlines of his single-payer “Medicare for All” plan, but he disingenuously left for another day details of how much his socialist scheme would cost and how it would be paid for.

That’s almost certainly because of the price tag, which the Health Policy Center of the Urban Institute estimated in May 2016 to reach a mind-boggling $32 trillion over a 10-year period. (Yes, you read that right—trillion with a “t.”)

The Washington Post was careful to explain that missing detail of Sanders’ legislation with delicacy: “The size of the tax increase, he said, would be determined in a separate bill.”

The Medicare for All Act of 2017 nonetheless has been enthusiastically embraced by 16 of Sanders’ Senate Democratic colleagues, fully one-third of their caucus. That’s a stunning turnabout from 2013, when similar legislation was introduced by Sanders and co-sponsors were nowhere to be found.

It’s a dubious testament to how far and how fast the Democratic Party has moved left in recent years.

Unlike in the late 1980s, the “B” word never crossed Sanders’ lips last week.

Thirty years ago, then-Mayor Sanders hosted a public access cable TV program, “Bernie Speaks with the Community,” and in a 1987 telecast, Sanders spoke with Dr. Milton Terris, the editor of the Journal of Public Health Policy.

“No. 1, you want to guarantee that all people have access to health care as you do in Canada,” he said, quickly adding however, that a government-run system in the U.S. would be prohibitively expensive.

“I think what we understand,” Sanders said at the time, “is that unless we change the funding system and the control mechanism in this country to do that—for example, if we expanded Medicaid [to] everybody, give everybody a Medicaid card—we would be spending such an astronomical sum of money that, you know, we would bankrupt the nation.”

For socialists like Sanders, price is no object when you’re spending other people’s money, but as former British Prime Minister Margaret Thatcher trenchantly observed, the trouble with socialism is that “eventually, you run out of other people’s money.”

And with a price tag of $32 trillion, “eventually” would be quick in coming.

Medicare’s trustees reported in mid-July that, barring major reforms, the system will become insolvent by 2029. Undeterred, the Vermont senator would floor the gas pedal en route to that fiscal cliff with the gusto of Thelma and Louise.

Sanders’ Medicare for All Act would greatly expand coverage to include prescription drugs, as well as mental health, vision, and dental care, while simultaneously doing away with patient copays. He says copays only become “a disincentive for people to get the health care they need.”

Evidence of the inefficiency and costliness of government bureaucracy to the contrary notwithstanding, Sanders told The Post, “[I]f we want to move away from a dysfunctional, wasteful, bureaucratic system, into a rational health care system that guarantees coverage to everyone in a cost-effective way, the only way to do it is Medicare for All.”

Now as in 1987, looking north of the Vermont border for support for his single-payer scheme, Sanders invited a Canadian doctor onto his podcast, “The Bernie Sanders Show,” the day after he rolled out his plan.

It would be fair to say that he didn’t get the rosy prognosis he had hoped for.

Dr. Danielle Martin, vice president for medical affairs and health system solutions at Women’s College Hospital in Toronto, acknowledged long wait times and other problems with the health care system of our northern neighbor.

“If I have a patient who’s got migraines, and I need advice about how to manage it, they might wait several months to see a neurologist for a non-urgent problem like that,” Martin said. “Or non-urgent surgeries, the classic example being a hip or a knee replacement.”

Sanders then asked how long it takes on average in Canada to get those routine procedures.

“Sometimes, it’s a few months; sometimes, it’s a year. … [S]ometimes, it’s been even longer than that, that people wait for a hip or a knee replacement,” Martin said. “And I think that is totally unacceptable. I don’t think that we should stand for it in our system.”

Whatever our health care system’s shortcomings might be, Americans certainly would never stand for such long waits for such routine procedures, nor for the enormous tax and spending increases the Sanders plan envisions.

That was true in 1987, and it’s still true today.