In agreeing to reopen the government for three weeks without funding for a border wall — previously his non-negotiable condition for ending the shutdown — President Trump clearly backed down.

Will Democrats now accept his call for bipartisan cooperation and seriously negotiate a compromise solution on the border-security issue?

Or will they bow to their hard-left wing and keep on pushing for Trump’s complete surrender?

The stopgap deal means 800,000 federal workers can return to work and will get their back pay. And it means debate on border-security funding can take place away from relentless negative media coverage of the shutdown’s effects.

Indeed, Trump acted just hours after La Guardia Airport was temporarily closed off when air-traffic controllers, after days of threats by their union, called in sick rather than work any longer without pay.

But if a border wall is no longer a precondition for ending the shutdown, Trump made clear it’s still very much on the table.

Moreover, he suggested strongly that if Congress doesn’t reach “a fair deal” in three weeks, he’ll declare a national emergency to fund the wall unilaterally.

At the same time, though, he indicated that he’s flexible on just what kind of a wall should be built — a significant nod to moderate Democrats who’ve said they favor some kind of physical barrier.

That gives both sides plenty of room to engage in genuine, honest negotiations — if Democratic leaders are willing.

Unfortunately, their track record is not promising: They’ve spurned every offer Trump has put on the table — including linkage to comprehensive immigration reform. Instead, they’ve kept on playing chicken.

Now that the president has blinked, it’s time to get serious. If they overplay their hand, it’s the Democrats who’ll be responsible for the consequences.