President Donald Trump has a chance over the next several days to deliver a punishing blow to Iran’s leaders and its struggling economy. He can refuse to extend U.S. economic sanctions relief that props up the 2015 nuclear deal.

That’s a tempting move, particularly as Iran’s leaders violently crack down on anti-government protesters. But Trump should resist the temptation. Here’s why:

-The nuclear deal is largely working as advertised so far.

-Even if the U.S. exits, its allies in Europe are likely to stick to the deal. So would Russia and China.

-Such a move would sharply increase the chances of a military conflict with Tehran.

-The recent protests in Iran began over the price of staples like eggs, but protesters quickly turned their fury on Supreme Leader Ayatollah Ali Khamenei and his corrupt regime. If the U.S. reimposes sanctions and Iran’s economy further tanks, guess who gets blamed? Not the mullahs. The Great Satan.

Iran’s leaders promised citizens that they would reap the benefits of the revived economy after the nuclear deal. But many young people in Iran don’t have jobs. Iran’s currency is worth less today than it was a few months ago. Here’s another ominous sign for the terror-sponsoring mullahs: Many protesters demand that Iran stop sending money to radicals, including Hezbollah, across the Middle East.

Rule No. 1 of geopolitical (and other) conflicts: When your opponent is heading for the canvas, don’t do anything that would break his fall.

Recall, too, that the aim of the nuclear deal isn’t to persuade Iran to drop its role as supreme troublemaker in the Middle East. It is supposed to stop Iran from developing atomic weaponry. And some of Trump’s Cabinet members — notably Secretary of State Rex Tillerson and Defense Secretary Jim Mattis — haven’t wanted to disrupt the agreement.

Trump has long talked of tearing up the deal and negotiating a better one. That’s far-fetched.

The shrewd move here is to leave the sanctions relief, and thus the nuclear deal, in place. Trump should bring to bear whatever pressure he can, at the U.N. or with America’s allies, to do three things: Rein in Iran’s ballistic missile program, eliminate sunset clauses in the deal under which restrictions on Iran’s nuclear program are phased out and expand inspections of Iranian military sites.

Yes, Tehran would oppose all three of those. But Trump might gain new ways to apply pressure. The Wall Street Journal reports that U.S. lawmakers — including Republican Sen. Bob Corker of Tennessee, chairman of the Senate Foreign Relations Committee, and Sen. Ben Cardin of Maryland, the top Democrat on the committee — are negotiating legislation that could set more stringent rules on when and how U.S. sanctions could be reimposed on Tehran.

If Trump extends the sanctions waivers, that isn’t a signal that the U.S. approves of Iran’s regime and its current behavior. But it is a way to maintain bargaining leverage against an adversary. As long as Iran depends on the money that flows from sanctions relief, Trump has a possible way to force Iran back to the table. Conversely, ending sanctions relief dares Iran to make a dash to build the bomb.

If that happens, Iran joins North Korea as a rogue regime with the planet’s most terrifying weapon.