Iran and the new Trump administration have already clashed with potentially disastrous consequences. The extreme vulnerability of the rapport between the two countries following the nuclear deal was on show recently as Iran tested a new long-range missile, and the Washington put Iran "on notice".
Yet, it is unsurprising that after 35 years of enmity, the revived US-Iran relationship would stumble as a radically different leadership takes power in Washington. Indeed, it might fall further should a similar shift occur in May after presidential elections take place in Iran. Does this mean the nuclear deal is doomed? It may be. But if so, it would be as much by default as by design. Four unexpected consequences of ill-conceived moves on Washington's part could intensify the conflict and collapse the deal. One smart move could save it.
1) Misreading Iran's bluster as more than an 'opening position'
The legality of the missile launch within the terms of the Joint Comprehensive Plan of Action (JCPOA), the nuclear agreement signed in 2015 by both governments, has drawn much speculation by American analysts, but no actual determination that it broke the letter of the law.
The Trump administration's inexperience in reading the tea leaves of Iran's foreign policy manoeuvres, however, has led it to decide, that, legal or not, the launch was an insult and a threat. So it hurled back a threat of its own.
Yet - much like Trump himself - the Islamic Republic is a prodder and doesn't back down when it gets a reaction. The result: public denunciations and shows of power will likely escalate.
2) Viewing diplomacy with Iran as useless, assuming that all it understands is force
To Trita Parsi, of the American Iranian Council (whose forthcoming book tells the inside story on how exactly the deal was done), to put shouty cards on the table without a soft-exit plan is to misunderstand the game of diplomacy, particularly when it comes to Iran.
What the Iranians do is play multiple hands - the public stage, the back-corridors, the phone lines - which Trump's predecessors did too. If the new administration only grandstands and doesn't balance tough words with secret meetings and smart compromises that suit both countries, the relationship will crash.
3) Mistaking Iran for a failed state
By placing it on the "List of Seven", Trump has put Iran in strange company. The other six are either at war, or lacking central government authority - unlike Iran, which has conducted high-level, government-backed international negotiations with the US over a significant security deal.
This is shaming for Iran, just as it was when George W Bush inducted Iran into the Axis of Evil after it publicly offered to materially support Washington's plans against al-Qaeda after 9/11.
As previous Iran nuclear negotiator Seyed Moussavian has frequently pointed out, Iran craves international respect, which once it felt forthcoming from Washington, contributed to the miraculous nuclear turnaround.
Trump, by including Iran among the seven Muslim-majority countries whose citizens he tried to ban from entering the US, has signalled that no matter what it does to burnish its international image, Iran will never get US respect. From that perspective, why would he care that not a single Iranian has been apprehended for terrorism inside the US? Misreading an adversary - or a friend - suggests the honeymoon is over.
4) Imagining Iran as having no good options
Iran today - post nuclear deal, free of UN and EU sanctions, restored as a regional power balancing Turkey and Saudi Arabia in Syria, and, critically, close to Russia - is not the lonely pariah of the past.
Its economy is big - it's the second largest producer of both steel and cars in the Middle East. But its trade goes not west but east, to the booming markets of China and India, and north, to Russia. A report this week by the conservative Washington Institute of Near East Studies noted that Iran's tight relationship with Moscow defies history, but reflects a solid pragmatism on both parts, that will be unfazed by Trump officials threatening to drive a wedge between them.
US administrations have consistently underestimated Iran's ability to survive international pressure, such as the travel bans and individual targets in Congress's newest "behavioural modification" sanctions passed last week.
Today, however, miscalibrating Iran's regional clout could damage the US' relations with both Moscow and Ankara, each of which have recently been wobbly and such a miscalculation could seriously compromise American regional plans to contain the Islamic State of Iraq and the Levant (ISIL).
To completely misjudge Iran, and allow the relationship of jabs and one-upmanship to deteriorate to a point where the use of force is the only option left on the table, would see the US going into war largely alone.
Though Israel might be at its side (and the already war-worn Saudi Arabia), Russia, supportive of Iran's recent "legal" missile test, would not sit back idly, but demand booty and threaten the use of force in equal measure. Islamists, all supporters of al-Qaeda, Jabhat Fateh al-Sham, ISIL or the Khorasan Group, would finally have their turn against the US as Donald Trump stumbles back into the morass from which President Barack Obama had withdrawn.
And the Europeans cannot be counted on. The European Union just re-iterated Iran's compliance with the JPCOA once again, signalling that it does not share Trump's view of Tehran's misdemeanours.
Yet all this could be avoided with one smart move. And one that fits with President Trump's own self-image as a deal-maker.
Offer a White Flag, and recast Iran as a valuable prospective market.
Hardliners and reformers in Iran agree on little, and neither would find much in common with Trump today, except to agree that the JCPOA isn't working well - currency regimes have been inadequately loosened, sanctions haven't been sufficiently lifted, companies are hesitant to sign deals, and international bank engagement remains anaemic.
For either side, destroying the JCPOA would not be difficult. But presidential greatness stems not from ripping up deals but, as Jimmy Carter with the Camp David Accords and Obama with Cuba both illustrated, it comes from making them work. By approaching Iran in a completely new way (as Richard Nixon did with China) and turning it into an economic opportunity for US companies - currently restricted from doing any business, no matter how lucrative, with oil-soaked Iran - it could be both a diplomatic, and a commercial coup for the new president.
Sadly, that's the last thing that Mr Trump would think of doing.
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