A fate as unpredictable as the reality of Donald Trump awaits the Iran nuclear deal. By refusing to certify it, and thus outsourcing any decision on the matter to 535 congressmen, Trump could cast a pall of uncertainty over the deal's future. But the ramifications of this dynamic are likely to ripple far beyond the deal itself.

To fully appreciate the broader significance of the deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), one would do well to consider the backdrop against which it came into being.

For all the legitimate criticisms levelled against Obama, it was thanks largely to his term in office that US engagement with the international order - repeatedly decimated by George W. Bush's uninhibited gangsterism - would undergo a groundbreaking shift. In the teeth of fierce opposition from his political rivals, Obama would stake the last remnants of his political capital to ensure US backing for two agreements of immense significance for global security: the Paris climate agreement and the Iran nuclear deal.

For its part, the nuclear deal would act as the single most comprehensive and definitive tool, which, as Germany's UN envoy, Harald Braun, put it, would "reassure the world that Iran's nuclear programme served exclusively peaceful purposes". Painstakingly negotiated between Iran and the P5+1 group of world powers, the deal imposed an unprecedentedly intrusive and exhaustive inspection regime on Iran's nuclear activities in return for the lifting of international sanctions that had devastated the country's economy, and with it the livelihood of millions of ordinary Iranians. The world - save the usual trigger-happy statesmen in Tel Aviv, Riyadh and Washington - could finally breathe a sigh of relief that a futile and catastrophic confrontation with Iran, one that would have made Iraq and Afghanistan look like brag-worthy success stories, was averted. The tired and unattainable agenda of regime change was at long last relinquished in favour of cooperation with Iran to jointly tackle the metastasising threat posed by the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group.

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So diffused were tensions between Iran and the US that even the capture of American sailors in Iranian waters - which could once escalate into a fully-fledged diplomatic crisis of monumental proportions - could now be resolved over a phone call between US and Iranian officials. (Some might contrast this to the international fiasco that ensued the 2007 arrest of UK sailors in Iranian waters.) Furthermore, this multilateral experiment had revived hope for other non-proliferation regimes to follow suit. If it worked with Iran, why can't it work with North Korea, Pakistan, or - dare we suggest - Israel? The cosmopolitan vision promoted by the JCPOA, as well as its import for global security, is reflected in the words of EU foreign policy chief Frederica Mogherini, who described the deal as "a milestone for non-proliferation, making everyone more secure in the region, in Europe, and in the world … the deal now belongs to the entire international community - not only to us who were in that [negotiating] room".

But perhaps the most telling testament to the JCPOA's significance for global security was its enshrinement in a resolution unanimously adopted by all fifteen members of the UN Security Council, including the US.

Placing the nuclear deal on life support will lend credence to the notion that covenants that enshrine the collective will of the international community may indeed be reduced to hollow shibboleths, and that it takes little more than a pathological ego equipped with scarce mental faculties to challenge the validity of agreed-upon safeguards against nuclear proliferation.

That initial optimism, however, has since collided with a grim reality called Donald J. Trump. Having crammed US foreign policy into 140 angry characters, Trump is now expected to decertify the nuclear deal - not least after twice confirming Iran's compliance with the JCPOA. This, despite the fact that the UN body charged with monitoring its implementation has confirmed eight consecutive times that Iran has lived up to its end of the deal. Men of the most hawkish disposition have advised against abandoning the deal. Tump's defence secretary and chairman of the joint chiefs of staff - hardly doves - have voiced their support for the deal and affirmed Iran's compliance with it. In addition, the other parties to the agreement (Russia, China, Germany, France, UK, EU) have signalled their unwillingness to renegotiate a deal that has thus far proven a success.

To be sure, Trump's decertification will not automatically abrogate the deal. It will, however, relinquish the power to determine its fate to Congress.This means that 535 lawmakers, many of whom are deeply beholden to defence contractors, corporate donors and their own fleeting political ambitions, will retain the power to trigger a cascading chain of events with potentially irreversible and incalculable consequences, only one of which is a path of confrontation with Iran. Almost overnight, US role in global security will devolve further from stakeholder to risk factor.

Since 1945, the will and word of US statesmen have either dictated or nullified the terms and conditions of global security. Regardless of whether the deal survives congress or not, by undermining an important document of global security, Trump will have signalled to the world that the risks of intercourse with the US should inspire more fear than its threatening posture ever could.

Placing the nuclear deal on life support will lend further credence to the belief that covenants that enshrine the collective will of the international community may indeed be reduced to hollow shibboleths, and that it takes little more than a pathologically-sized ego equipped with modest mental resources to challenge the validity of agreed-upon safeguards against nuclear proliferation.

In the foreseeable future, the onus of proving good faith will rest squarely on the shoulders of US leaders.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.