With the recent election of Donald Trump and the voters’ corresponding rejection of recent U.S. policies both foreign and domestic, one highly important question has arisen: What does Trump’s election mean for Barack Obama’s cherished Iran nuclear deal? Trump’s campaign talk on this issue was very hawkish, but not very specific. He seems to understand the extremely unfavorable nature of the deal, but it’s unlikely he has given much thought to how he might go about changing its terms or withdrawing altogether, or about what an alternative policy should be. Indeed, forming a coherent policy on Iran’s nuclear program must come first, before any decision on what to do about the existing deal.

There is no question the United States can withdraw from the deal. Despite all the teeth-gnashing and hair-pulling on the other side about the supposed sanctity of the deal, no international agreement can be legally binding on the United States without the express approval of Congress. Either the Senate ratifies a treaty, or Congress passes legislation imposing an agreement’s terms into U.S. law. Obama knew this full well, being a “constitutional scholar” and all, and he chose deliberately to avoid Congress, instead using the UN Security Council. Sorry, Mr. President, but that won’t answer. No law tops U.S. law when it comes to the obligations on our nation.

As we said at the time, Obama’s cynical decision to attempt an end run around Congress would be doubly damaging:

This [using the UN Security Council] allows Obama to frame a potential congressional rejection, however unlikely, as an act that would isolate the United States from its negotiating partners. In addition to the damage done to our national security by accepting this deal, Obama has thus laid the groundwork for a future president who will have to damage our international standing by withdrawing from the deal.

Unfortunately, if President-elect Trump does act to withdraw from the deal, or even attempts to strengthen its terms, it will no doubt damage relations with friends and enemies alike. France, Great Britain and Germany all prefer to bury their heads in the sand and hope for the best. Russia and China will whine about our undercutting the UNSC. And Democrats will make no end of partisan political hay out of the U.S. reneging on the deal, domestically hated though it may be. These are all valid concerns, and must be weighed against what we might gain.

The nature of the deal’s beneficial terms for Iran can be gauged by how quickly Iran started shouting after Trump won the election. Everyone from Supreme Leader Ali Khamenei on down offered their views, most of which boiled down to insistence that the deal must be maintained as is. President Hassan Rouhani claimed, “Iran’s understanding in the nuclear deal was that the accord was not concluded with one country or government but was approved by a resolution of the UN Security Council and there is no possibility that it can be changed by a single government.” Others in high positions have said the same.

The first order of business for Trump and his team is to flesh out their Iran policy. That policy must be seriously and carefully considered, and then presented coherently to the public and our allies. It won’t do simply to announce on Jan. 21 that we’re withdrawing or seeking to modify the deal without first presenting an alternative and the rationale behind it. It’s conceivable that a carefully considered Iran policy might conclude that staying in the deal and enforcing it to the letter is our least bad option. Either way, the new administration needs to start immediately.