President Donald Trump walks off after delivering a statement on the Iran nuclear deal from the Diplomatic Reception Room of the White House. Picture: Evan Vucci/AP

Washington - The nuclear deal struck with Iran three years ago was far from perfect, but President Donald Trump's decision to abrogate it over the opposition of our European allies and without a clear strategy for replacing it is reckless and, most likely, self-defeating.

Trump has opened a rift with Britain, Germany and France, who were partners to the pact along with Russia and China, and he has handed Iran's Islamic regime some unfortunate opportunities.

In a bombastic address, Trump claimed "we cannot prevent an Iranian nuclear bomb under the decaying and rotten structure of the current agreement." What he did not acknowledge is that international inspectors as well as senior members of his own administration have confirmed that Iran has complied with the accord, which has vastly reduced its stock of enriched uranium and made it extremely difficult for the regime to develop nuclear weapons in the next decade. 

The president held out the prospect of "a new and lasting deal" that would cover not just nukes but also Iran's development of missiles and interventions in Middle Eastern wars. But he offered no road map for achieving that ambitious goal.

Read more: Trump poised to pull US out of Iran deal

The first consequence of Trump's decision could be conflict with the Europeans. The sanctions regime that Trump reimposed seeks to force other countries to reduce oil purchases and other business with Iran, and it threatens sanctions if they do not.

European governments, which have said they will not renounce the nuclear deal, may fight any US attempt to enforce the restrictions, including with their own sanctions.

Having tried and failed to satisfy Trump's objections to the agreement without breaking it, they are unlikely to willingly collaborate in a new US attempt to crush the Iranian economy.

Iran and European governments could agree to continue the pact in defiance of Washington. But Iran's hard-line military and security apparatus, which has always opposed the accord, will press to resume uranium enrichment, restrict inspections or perhaps even race for a bomb.

How would Trump stop such a breakout, short of war? One reason the nuclear deal was struck was a conclusion by the administrations of both George W Bush and Barack Obama that military action was a risky and uncertain means to prevent an Iranian bomb.

Trump was pushed to exit the deal by Israeli Prime Minister Benjamin Netanyahu and Saudi ruler Mohammed bin Salman, whose countries are already engaged in low-level wars with Iran. But the chief of staff of Israel's own army has said that the nuclear deal is "working and putting off realisation of the Iranian nuclear vision by 10 to 15 years."

Trump's decision could eliminate that grace period while doing nothing to stop ongoing Iranian aggression in Syria, Yemen and elsewhere. The Saudis and Israelis may hope that Trump's decision will draw the United States back into the Middle East through a confrontation with their enemy. The president has frequently said that he has no wish for further Mideast wars; his decision has made one more likely.