President Trump's Iran address creates uncertainty about the long-term survival of the two-year-old nuclear deal. It opens the door to Congress to find ways out of it, even as he threatened — yet again — to use his power as president to break the deal himself.

But for now, the deal stands — with the administration itself acknowledging it's better to have it than to break it.

Instead, the administration says it wants to redefine the U.S. relationship with Iran beyond the nuclear agreement. Trump reviewed Iran's missile tests and support for Hezbollah, Hamas and Iraqi militias that have targeted U.S. troops.

Why the deal wins — for now

For all his denunciations of the deal, Trump's move Friday is another instance in which he has passed up a chance to break it.

True, he didn't certify the deal again, as he has twice before under a recurring 90-day review stipulation. But that does not take the U.S. out of it.

The certification isn't part of the deal. It's just a requirement Congress put on President Barack Obama to make him own a deal Congress didn't like. Trump's refusal to certify just puts the onus on Congress now to do something about it.

And Trump isn't even asking Congress to take the U.S. out of the deal — as it could by imposing the sanctions that were lifted in exchange for Iran allowing limits on its nuclear program.

It's useful to look at the reason Trump used for not recertifying the deal. Congress gives the president a menu of reasons.

The president could have asserted that Iran is not in compliance. But "We don't dispute that they're under technical compliance," Secretary of State Rex Tillerson told reporters Thursday, before the president made his announcement. (Tillerson did say the requirements for complying aren't strong enough.)

Trump also could have said that the lifting of sanctions — part of the deal — was no longer vital to U.S. national security. But then how could he reasonably lift the sanctions again when they come up for regular renewal? Trump just waived some again last month, keeping the U.S. in the deal.

In his speech Friday, Trump carefully stated that he refuses to certify the deal because he can't ensure that — using phrasing from Congress — the sanctions relief in the deal is "appropriate and proportionate" to what Iran gives on its end of the bargain.

Even there, Trump could ask Congress to impose sanctions that would break the deal — but he is not. Instead, he is asking for new laws that would snap sanctions in place if Iran tries to ramp up its nuclear program.

The administration has also called for the deal to be renegotiated. But on Thursday, Tillerson acknowledged that's unlikely — just as European allies who spent years working on the deal have stressed.

What Iran gets

Trump's threats to eventually bring down the deal mean Iran can now blame the U.S. for shaking up an agreement that it is widely seen as complying with and is backed by Europe, Russia, China and the U.N. Security Council. As some backers of the deal worry, it's hardliners in Iran who will benefit most because they will say the moderates were mistaken to make a deal that is about to fall apart because of a fickle and hostile United States.

Meanwhile, Iran will continue to get its sanctions relief and do business with other signatories.

The administration did impose new sanctions (not covered by the deal) Friday on the Iranian Revolutionary Guard Corps, a wing of Iran's military that trains and backs militias around the region. But the Revolutionary Guard is already heavily sanctioned by the U.S.

European business rolls on

European diplomats have been lining up to urge the Trump administration to stay in the deal. They're nervous that an anti-Iran current in Congress could eventually spoil the agreement. And they worry that if the U.S. exits the deal, it could try to punish the companies from Europe that are doing business with Iran.

For now, they can go on developing things like aircraft, auto and oil deals with the Islamic Republic. And Trump's threats have drawn attention to the possibility that Europe and Iran could just continue with the deal and without the U.S.

European countries have shown some more willingness to consider other actions to pressure Iran to rein in its hardliners. That could be because of Trump's threats to scrap the deal.

Trump keeps the pressure on

Threats for future steps may have more impact than anything else Trump did on Iran this week. By staying in the deal, he keeps those threats alive.

And that means Trump can continue to raise Iran as an issue, as he did throughout his campaign and since taking office. That goes over well with his supporters, especially those who recall that the Iran agreement was a hallmark of the Obama administration.

"In the event we are not able to reach a solution working with Congress and our allies, then the agreement will be terminated," Trump said Friday. Considering his efforts to dismantle other Obama legacies — like Obamacare or leniency for undocumented child immigrants — this could be a step toward eventually pulling the U.S. out of the Iran deal.

Or it could remain a threat, while Trump carefully pairs his denunciations with careful measures to keep the deal in place.

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