In quitting the Paris Accord, President Trump on Thursday did nothing to shift the course of US environmental policy — not even on carbon emissions. But he did put the world on notice that no president can unilaterally commit this nation to such far-reaching agreements.

The Constitution is clear: No treaty is binding on the US government unless ratified by the Senate. That tanked the Kyoto Protocol, a 1997 anti-warming treaty that the Senate rejected 95-0. And it would’ve killed the Paris deal that President Obama signed in 2016 — except that his negotiators shaped an “agreement” that wouldn’t go to the Senate.

But one that still would’ve been used to rewrite US law, if the courts went along. (And a President Hillary Clinton’s judicial picks would have ensured that they did.)

In fact, Trump had already abandoned the Paris goals by junking Obama’s Clean Power Plan. Yet he’s not turning back the clock. He’s just saying no to what Obama sought to impose — a rush to a low-carbon America at huge economic cost.

Under Paris, as Trump noted, the United States would’ve had to close all its coal plants, even as China builds hundreds more — and coal still generates a third of US electricity.

Yet America will continue to cut its carbon emissions: They’re already down by a fifth since 2000, thanks to fracking and the gradual replacement of coal plants with natural-gas ones. That’s better than Europe did as it implemented Kyoto by making electricity cost twice as much as it does here.

Nor did Paris make sense. As Danish economist Bjorn Lomborg notes, it entails costs of over $1 trillion a year to shave 0.36 degrees Fahrenheit off global temperatures by 2100 — a tenth the reduction it said is necessary.

The better response, Lomborg argues, is massive R&D in non-carbon power — so that humanity needn’t impoverish itself to “save the planet.” As he pursues smart post-Paris policies, Trump ought to boost outlays for “green energy” R&D.

America has far cleaner air and water than it did 50 years ago, and more parkland. It should continue those trends, and keep reducing its carbon emissions — democratically.

What the nation won’t do, thanks to the president, is devastate its own economy against the public’s wishes in order to satisfy the global elite. Count this as a major Trump promise kept.