If it’s not a Christmas miracle it should at least qualify as a Festivus feat of strength. On Sunday CNN’s Jake Tapper managed to get Sen. Bernie Sanders on the record endorsing President Donald Trump’s tax cuts for middle-income earners.

To put the miraculous nature of this admission in context, even in the heat of a presidential campaign the Vermont Marxist proposed to raise federal taxes by more than $6 trillion over the course of a decade. Granted even that historic hike would not have nearly covered the expanded costs of a Sandernista government. During that same campaign for president in 2016, Mr. Sanders admitted to new spending plans adding up to $18 trillion.

Yes, Mr. Sanders talks about taxing the rich but even he must know that his single-payer schemes could never be financed without a massive burden on the bottom 99%. Yet he’s now admitting that at least some taxpayers deserve relief.

Here’s the key exchange on CNN:

TAPPER: I understand you’re not a fan of the tax bill. You don’t like the large corporate tax cut, and you are not happy with the tax cuts for the wealthy. But, according to the Tax Policy Center, next year, 91 percent of middle-income Americans will receive a tax cut. Isn’t that a good thing?

SANDERS: Yes, it is a very good thing. And that’s why we should have made the tax breaks for the middle class permanent. But what the Republicans did is made the tax breaks for corporations permanent, the tax breaks for the middle class temporary.

CNN’s official transcript makes clear that Mr. Sanders still has a lot of gripes about the overall Trump tax package. But he is surely aware that the reason Republicans had to set expiration dates on certain provisions was the budget reconciliation process necessitated by the unwillingness of Democrats to negotiate on tax reform. And even if he ignores the voluminous research showing that cuts in corporate income taxes lift wages for workers, he probably knows that pension systems and other retirement plans heavily rely on investments in corporate America.