President Donald Trump speaks during a session on reforming the United Nations at U.N. Headquarters in New York, September 18, 2017. Lucas Jackson | Reuters

President Donald Trump won't say yet whether he is going to "decertify" the Iran nuclear deal — but his decision could impact America's international standing as much as Iran's. Trump told reporters on Wednesday that he has already made up his mind on the international agreement next month, though he did not reveal what the decision is. He has taken a much harder line toward Iran than his predecessor President Barack Obama. Under a law passed by Congress, the president must certify every 90 days whether Iran remains in compliance with the landmark, 2015 pact, which lifted severe economic sanctions on Iran in exchange for the country freezing its nuclear activities. NBC reported Wednesday that Trump is leaning toward decertifying the agreement.

A U.S. decertification would not necessarily end the deal — the U.S. just wouldn't be part of it anymore. The Europeans won't return to sanctions so quickly. If this enables Airbus to beat out Boeing, they'd be delighted. Robert Litwak international security expert, the Wilson Center

If the president does decide to decertify the deal and possibly reimpose sanctions, "we'd be in uncharted waters," says Robert Litwak, a member of the National Security Council under President Bill Clinton, now an expert on international security at the Wilson Center. "The U.S. would risk isolation, not Iran." Litwak said he believes there's a logical argument to be made that Iran isn't cooperating with the spirit of the deal — by testing missiles, funding and arming terrorist groups including Hezbollah and fueling civil wars in Yemen and Syria. But those issues aren't actually included in the 2015 agreement known as the Joint Comprehensive Plan of Action, which was signed by Iran, the United States, France, China, Russia, the United Kingdom, Germany and the European Union. Proponents of the agreement argue it's the best way to keep Iran from becoming a nuclear-armed nation, at least until the sunset provision on the deal expires in eight years.

If the U.S. decertifies the deal, "the ball immediately goes to Iran's court," said Michael O'Hanlon, a foreign policy expert at the Brookings Institution. Iran "could have their cake and eat it too." It would be possible, O'Hanlon explained, for Iran to keep the benefits it gets from the agreement — namely, to continue to legally export oil. Then, a few years down the road it could argue that the agreement is null due to a lack of compliance from the United States. It could then resume nuclear activities. That's not an attractive prospect for U.S. decision-makers, because it would force them to make a choice: either attack Iran's nuclear facilities, or push for new sanctions from a group of countries that will almost certainly be reluctant to give up business ties with Iran.

Is Trump Bluffing?

"It would be totally irresponsible to decertify," according to Gary Sick, a professor at Columbia University who served on the National Security Council under Presidents Reagan, Ford and Carter. Sick added that "decertification is actually contrary to U.S. interests by all standards." Sick says it's unclear whether Trump will make the move or if he's just trying to make it clear "that he doesn't like the deal negotiated under President Obama." If President Trump separates from the agreement, the deal may simply live on without the United States.

Iranian workers walk at a unit of South Pars Gas field in Asalouyeh Seaport, north of Persian Gulf, Iran November 19, 2015. Raheb Homavandi | TIMA

"A U.S. decertification would not necessarily end the deal — the U.S. just wouldn't be part of it anymore," said Litwak. "The Europeans won't return to sanctions so quickly. If this enables Airbus to beat out Boeing, they'd be delighted." Iran has increased trade with Asian and European countries since the agreement was signed, but not with the United States. However, the U.S. could impose new sanctions that make it risky or impossible for companies to do business with Iran, by declaring that they can't do business in both Iran and the United States. "Iran knows perfectly well it's a middle level power with a middle level economy and if companies and countries have to choose, it would be hard to go against the U.S.," said Sick at Columbia University.

'Wedge issue'