Apologists for the deal answer that the price is worth paying because Iran has put on hold much of its production of nuclear fuel for the next several years. Yet even now Iran is under looser nuclear strictures than South Korea, and would have been allowed to enrich as much material as it liked once the deal expired. That’s nuts.

Apologists also claim that, with Trump’s decision, Tehran will simply restart its enrichment activities on an industrial scale. Maybe it will, forcing a crisis that could end with U.S. or Israeli strikes on Iran’s nuclear sites. But that would be stupid, something the regime emphatically isn’t. More likely, it will take symbolic steps to restart enrichment, thereby implying a threat without making good on it. What the regime wants is a renegotiation, not a reckoning.

Why? Even with the sanctions relief, the Iranian economy hangs by a thread: The Wall Street Journal on Sunday reported “hundreds of recent outbreaks of labor unrest in Iran, an indication of deepening discord over the nation’s economic troubles.” This week, the rial hit a record low of 67,800 to the dollar; one member of the Iranian Parliament estimated $30 billion of capital outflows in recent months. That’s real money for a country whose gross domestic product barely matches that of Boston.

The regime might calculate that a strategy of confrontation with the West could whip up useful nationalist fervors. But it would have to tread carefully: Ordinary Iranians are already furious that their government has squandered the proceeds of the nuclear deal on propping up the Assad regime. The conditions that led to the so-called Green movement of 2009 are there once again. Nor will it help Iran if it tries to start a war with Israel and comes out badly bloodied.

All this means the administration is in a strong position to negotiate a viable deal. But it missed an opportunity last month when it failed to deliver a crippling blow to Bashar al-Assad, Iran’s puppet in Syria, for his use of chemical weapons. Trump’s appeals in his speech to the Iranian people also sounded hollow from a president who isn’t exactly a tribune of liberalism and has disdained human rights as a tool of U.S. diplomacy. And the U.S. will need to mend fences with its European partners to pursue a coordinated diplomatic approach.

The goal is to put Iran’s rulers to a fundamental choice. They can opt to have a functioning economy, free of sanctions and open to investment, at the price of permanently, verifiably and irreversibly forgoing a nuclear option and abandoning their support for terrorists. Or they can pursue their nuclear ambitions at the cost of economic ruin and possible war. But they are no longer entitled to Barack Obama’s sweetheart deal of getting sanctions lifted first, retaining their nuclear options for later, and sponsoring terrorism throughout.

Trump’s courageous decision to withdraw from the nuclear deal will clarify the stakes for Tehran. Now we’ll see whether the administration is capable of following through.