If President Trump walks away from the Iran nuclear deal, after again calling on Congress to unilaterally "correct" it during his State of the Union address, it would be the third major international agreement he has ditched.

With Europe, Russia, China and Iran unwilling to renegotiate, such a move would set the stage for withdrawal. But unlike the Trans Pacific Partnership and Paris Climate Agreement, where other parties moved on without the U.S., blowing up the Iran deal would have serious repercussions.

Nuclear sanctions “snap back,” setting up no-win trade disputes with countries and companies that continue to do business in Iran. Iran would then not only continue to test missiles and pursue its interests in places like Syria, but also resume the very nuclear activity the agreement actually stopped.

But none of this is necessary, since Trump’s Iran policy is working.

Even with the nuclear deal intact, the Trump administration has imposed additional sanctions against entities linked to Iran’s missile program and support of terrorist organizations.

The recent public protests across Iran over its dismal economic outlook and ensuing crackdown provide the administration a significant opportunity to discourage further international investment in Iran, potentially widening the wedge between the Iranian government and its people the protests revealed.

Blowing up the nuclear deal is a lose-lose-lose proposition. It undermines the U.S. relationship with key allies and makes Russia and China appear to be the more responsible international actors. And it gives the Ayatollah a gift-wrapped opportunity to point to yet another American conspiracy and shift the blame for Iran's troubles to the Great Satan.

The bottom line: In Trump’s world, when policy and politics collide, politics prevails. Regardless of the global consequences, Trump may well terminate the Iran deal just because he said he would. He sees this as clarity. To the rest of the world, it's more chaos.

P.J. Crowley is a former Assistant Secretary of State and author of "Red Line: American Foreign Policy in a Time of Fractured Politics and Failing States."