On Tuesday, President Donald Trump added Iran to his very short list (two names) of major nuclear crises that demand immediate and relentless focus. He defied European allies and made good on long-telegraphed threats to withdraw the US from the 2015 Iran nuclear deal.

The president didn’t mince words. “It is clear to me that we cannot prevent an Iranian nuclear bomb under the decaying and rotten structure of the current agreement,” he said. “The Iran deal is defective at its core.” Trump says the US will now begin reinstating stifling sanctions on Iran’s still-staggering economy.

We supported the deal as negotiated. But our endorsement was reluctant, essentially for the reasons Trump now cites. We share his goal of perpetually denying Iran the ability to build nuclear weapons and launch an attack. But at each suggestion of nixing the deal, we’ve asked the question now resonating in capitals worldwide: What happens if Iran is freed to pursue nukes?

Trump’s high-stakes gamble to break with allies and reimpose sanctions could be the first major step to a renegotiated pact with Tehran that will satisfy his demands: to rein in Iran’s ballistic missile program, eliminate sunset clauses in the pact, and expand inspections of Iranian military sites.

Or scuttling the deal could unleash Iran’s drive to build a nuclear weapon and trigger a military conflict.

Or … something in between.

Much depends on how Western companies doing business with Iran react, how Russia and China attempt to exploit this crisis (and they will), and whether European countries grudgingly go along with Trump.

Early indications Tuesday: European governments, some of them sensitive to losing business opportunities, won’t go along. President Emmanuel Macron of France, Prime Minister Theresa May of Britain and Chancellor Angela Merkel of Germany called the US pullout a matter of “regret and concern.” They said they remain committed to the accord and urged Iran to do the same.

Remember, Iran’s economy is a basket case, so the Tehran government has incentives to placate the West by keeping its nuke program muted. In January, protesters surged and seethed in street protests over prices -- and the fumbling leadership of Ayatollah Ali Khamenei. In the coming weeks, Iran’s leaders may elect to bluster angrily, blame the Great Satan, but not actually do much.

There’s plenty of diplomatic drama to come. But the context here -- the stability of the world in the age of devastating weaponry -- is more bracing than the endless push and pull of geopolitics.

For more than six decades, the US and its allies have sought to halt the spread of nuclear weapons. In 1953, President Dwight Eisenhower promoted the paradoxical “Atoms for Peace” initiative: Give countries nuclear know-how for energy purposes to stop them from developing nuclear weapons. It didn’t work as well as the US hoped. Peaceful nuclear expertise spread but so did weapons knowledge -- to India, Israel, Pakistan and, more recently, North Korea. How long before Iran has nuclear bombs?

As each new rogue member expands the nuclear club, so does the prospect of a mushroom cloud over New York or Chicago or Paris or Berlin or London or Moscow or Beijing. As does the possibility that affiliated terror groups will obtain a nuke and use it without providing a return address for retaliation.

On Tuesday, Trump mentioned the other nuclear crisis on his short list -- North Korea. Secretary of State Mike Pompeo is talking with Pyongyang to prepare for Trump’s meeting with dictator Kim Jong-un. The goal: Persuade Kim to surrender his nuclear arsenal -- which threatens not only the region, but US cities.

But tearing up the Iran deal -- arguably proving the US is untrustworthy -- doesn’t give Kim incentive to strike an accord with Trump.

Trump says “America no longer makes empty threats.” Nor, as the world sees, does it keep all its commitments. Beyond the boundaries of Iran’s laboratories, that breaking of this nation’s word could be the most perilous side effect of Trump’s action Tuesday.

Trump now confronts two rogue regimes, one a nuclear wannabe, one a growing nuclear power. His goal is to find a combination of incentives and threats to turn back the nuclear doomsday clock.

We’re skeptical that Trump helped that cause by his bombastic exit from the treaty without America’s allies in tow -- and without an answer to that crucial question: What happens if Iran is freed to pursue nukes?


Editorial by Chicago Tribune

(Tribune Content Agency)