President Donald Trump walked out of his Tuesday meeting with Volodymyr Zelensky with a hope-filled revelation: Ukrainians can take their country back. All of it.

After his sitdown with Ukraine’s president. Trump posted on Truth Social: “I think Ukraine, with the support of the European Union, is in a position to fight and WIN all of Ukraine back in its original form” and “who knows, maybe even go further than that!”

This is a game-changing 180; as recently as mid-August, the prez’s position was that peace would require Kyiv to cede at least some territory to Moscow.

His reasons for now saying Ukraine can win: Russia looks like a “paper tiger,” crippled after “fighting aimlessly for three and a half years” in a war that should have taken “less than a week to win.”

All evidence points to the Russian bear being as mangy as Trump suggests: The Kremlin’s drone incursions into Poland and Estonia’s airspace (and possibly Denmark’s, too) look like desperate scare tactics, meant to panic the West into fearing a wider war.

Meanwhile, its economy now relies almost entirely on war manufacturing and oil exports — with the latter hit hard by Kyiv’s wildly effective strikes on refineries.

Cheers the president: “Putin and Russia are in BIG Economic trouble, and this is the time for Ukraine to act.”

Amen to that, sir: Now give Kyiv what it needs to do the job.

Trump has already said Washington will keep selling our NATO partners weapons to dish out to Ukraine as they see fit; he can up the pressure for peace by ensuring Kyiv gets an influx of much-needed artillery, air-defense systems and drones and lifting all restrictions on the use of Western-supplied weapons.

And hit the “paper tiger” with another hammer — secondary sanctions against countries still buying up Russian oil, primarily China and India.

Trump has waffled on this, threatening Vladimir Putin with a 10-day deadline back in July, then this month hinging fresh US sanctions on new demands on Europeans.

And Putin’s only increased his behind-the-lines attacks on civilians, while throwing troops into the front-line buzzsaw to gain bare yards of territory — hoping that terror and some air of inevitable Russian victory will break his enemies’ will.

The longer the near-impasse goes on, the more needless deaths on both sides.

Our president needs to stick to his new, tough line: No more telegraphing to Putin that he’s willing to force Ukraine to accept the impossible.

Now is the time to be decisive: Moscow is on its back heel; an end to this war is within reach.

Ukrainians can land the final blow — and Trump can help them do it.