So the Iran nuclear deal is dead, at least as far as the U.S. is concerned. This is a grave mistake, because as flawed as the deal was — and it was flawed in many ways — it was better than nothing.

President Donald Trump's initiative shows no sign of having been thought through. It has divided the U.S. from its allies in Europe, and it's capable of dangerously destabilizing the region. But the mistake has been made, and the question now is where the U.S.; Iran; the five other nations that signed the deal; and America's vital ally in the region, Israel, go from here.

Trump's address was vague about the details, but the U.S. Treasury indicated that sanctions will be reinstated in stages after 90 days. This short timeframe suggests the administration has no interest in a last-minute attempt to improve the deal with its European allies and Tehran.

Iran and the European parties to the deal say they'll try to maintain it despite the U.S. withdrawal. That's worth doing, because it would leave the door open to negotiating a new and better deal down the road. A revised pact ought to lengthen the timeframes under which Iran is barred from developing nuclear weapons, curb its ballistic-missile testing, and improve the system for inspecting Iranian sites.

In looking ahead, bear something else in mind: Iran's nuclear ambitions aren't the only threat the country poses to U.S. interests. The atomic-weapons program is one piece of a larger goal — to become the power broker in the Middle East, to exert control over a string of countries all the way to the Mediterranean, to destabilize the Arab states, and to threaten Israel's existence.

Frustrating that ambition should be the overriding goal, and merely ending the nuclear deal won't advance it. What's needed is a bigger plan — a scaled-down version of the containment strategy that won the Cold War.

That will require mending fences with the Europeans; helping Israel and the Gulf Arab states coordinate and improve their intelligence and security systems; cracking down on Iran's illegal weapons shipments in the region; and persuading China and Russia that the Tehran regime is a threat to their interests as well as to the West's.

Trump's killing of the Iran nuclear pact is a setback to that larger goal. But it needn't be a fatal one. Iran is playing a long game. The U.S. and its allies must also keep their eyes on the bigger picture.

Bloomberg View