More details to come, he promised, and it’ll be interesting to see how he pays for it all. But Trump’s impulse to roll back taxes to jump start the economy is hopeful news.

Indeed, it’s something both Democrats and Republicans can support — or should, anyway.

Why? Consider: Conservatives believe taxes throttle growth, because they weaken the incentive to invest. Why put your money (and your back) into a risky endeavor if the government’s going to come and seize a big chunk of any profits you make? No investment means no jobs.

Liberals, of course, love taxes. And Hillary Clinton is staking much of her candidacy on a vow to raise them, at least on wealthier folks.

But liberals also think deficits stir demand and boost the economy; they just like to create those deficits with spending rather than tax cuts. President Obama, recall, raised taxes — but jacked up spending more, doubling the debt.