Since winning the greatest political upset in modern American history, Donald Trump has since taken on the US defense industry by publicly questioning whether Boeing was overcharging the American taxpayer for its government contract to build the next version of Air Force One, the presidential jet.

Trump subsequently doubled down by questioning the cost effectiveness of Lockheed Martin’s Join Strike Fighter program, which produces the most sophisticated fighter jet in history – also known as the F-35 – and is bound to preserve US air superiority for decades to come.

But interestingly enough, he has so far not commented on Boeing’s agreement to sell 100 planes to Iran Air, a contract valued at more than $18 billion based on list price, though such deals can include big discounts. While it is possible that Trump’s decision not to comment on Boeing’s Iran agreement is tied to his apparent desire to remain unpredictable on the world stage, his tweets initially wiped out hundreds of millions of dollars in market cap.

The Iran agreement

In the meantime, the president-elect – against all odds – is uniquely positioned to preserve President Barack Obama’s fractious foreign policy legacy which primarily rests on the success of the Joint Comprehensive Plan of Action with Iran, or JCPA.

The very same US foreign policy establishment that now chides Trump for seeking détente with Moscow so that common ground can be found on Syria to bring about a long-term ceasefire, ridiculed candidate Obama’s campaign promises eight years ago to turn a new page with Iran.

Just as Obama rightfully challenged conventional wisdom on how to bring Tehran to the negotiation table over its dangerous nuclear program, which at the time served as the key impediment to international peace and stability until the historic nuclear agreement was reached last year, Trump’s unorthodox foreign policy approach – coupled with his unpredictability – could serve as an important deterrence to ensure that Tehran lives up to its obligations under the agreement.

During the campaign, Trump never explicitly called for nullifying the JCPA but instead criticized it as a “horrible deal.” His core criticism of the JCPA is based on a false premise: that the agreement requires the US to pay Iran $150 billion. To the extent that Iran will reap a financial windfall from the JCPA, it will be from the return of Tehran’s own assets and proceeds from oil sales that have been frozen in international accounts abroad. This is not U.S. money, as he alleges.

Should Tehran comply, Trump would not only preserve Obama’s Iran legacy, but could use the implementation of the JCPA as a test to determine whether a broader strategic framework that rolls back Tehran’s regional agenda coupled with joining forces with Iran and Russia to fight ISIS could be found.

A multilateral approach to defeat ISIS

With a creative diplomatic approach, one that recognizes the legitimate interests of Saudi Arabia, Turkey, Iran and Russia, Trump could potentially reestablish from the outset of his administration the regional balance of power – through robust US-leadership – by including the aforementioned states into an integrated regional security framework that builds on the various military victories against ISIS by the US-led International coalition and Iraqi security forces. This too, would help preserve Obama’s legacy to help defeat the terrorist group once for all.

While opponents of Trump’s unorthodox campaign have questioned his temperament, the combination of his unpredictability and Washington’s long-standing alliances, coupled with his desire to turn a new page with President Vladimir Putin of Russia, could force the competing parties to the Syrian conflict to make the necessary compromises to bring a permanent ceasefire to the war-torn country while strengthening the various mechanisms required for establishing an actual regional coalition determined to defeat ISIS and other extremist groups in Iraq.

The obvious price for Trump to secure Moscow’s cooperation to defeat ISIS will be the survival of the embattled Syrian regime of Bashar al-Assad, which for obvious reasons cannot be toppled as it enjoys robust Russian military support. A US-Russian détente could pave the way for the establishment of a humanitarian safe zone in Syria to help stem the massive wave of desperate refugees seeking a better future in Europe.

Would a Clinton presidency trigger a crisis with Russia?

Despite Trump savaging his Democratic rival, Hilary Rodham Clinton, by equating her to a “third-term Obama-presidency,” had she prevailed on Election Day, there is little doubt that Washington would have faced its most significant crisis with Moscow in decades as it would have been difficult for her to walk back her contentious campaign rhetoric against Russia which primarily centered on allegations that it had interfered in the US presidential elections.

In the process, Obama’s fragile foreign policy achievements in the Middle East would likely have been reduced to rubble by a vindictive Russia and an opportunistic Iran seeking to capitalize on renewed US-Russian tensions.

These dynamics would have made the world far more dangerous as they would leave Tehran with little incentive but to violate Obama’s crown foreign policy achievement, the peaceful solution to Iran’s dangerous nuclear program. In light of the contentious presidential campaign, it is beyond ironic that Trump, and not Clinton, is the best positioned to preserve Obama’s foreign policy legacy.

In the meantime, whether or not Trump will allow the Boeing agreement with Iran to move forward, there is little room for maneuverability as rejecting it could lead to the unraveling of the JCPA and with it Washington is back to square one.

Tehran, however, will likely remain in suspense over whether it too can expect a tweet from the US president elect; and while it is listening, Trump has the opportunity to reshape the US-Iran relationship – and with it the region at large – for the next decade and beyond. But, the outcome, as anything these days, is unpredictable.

This article was originally published by Al Arabiya.