In some respects, US President Donald Trump and the Iranian theocratic regime deserve each other.
Neither respect international agreements, except when it suits their purposes. Trump's badmouthing of the Iranian nuclear agreement is of one with his behaviour over the Trans-Pacific Partnership, the Paris climate agreement, the North American Free Trade Agreement, and US alliances more generally. On the other hand, the Iranian regime has often flouted international agreements in even more dramatic fashion - taking US diplomats hostage for more than a year was just the most spectacular and egregious example.
Trump, however, has some valid points. The Iranian regime is indeed a major player in conflicts across the Middle East, being actively involved in Syria and Iraq, interfering in Bahrain and Yemen, and relentlessly advancing its long-range missile technology. Trump says that in continuing with these activities, Iran is acting against the spirit of the nuclear agreement, the Joint Comprehensive Plan of Action (JCPOA). But the agreement is all about nuclear matters, not these other bugbears.
In many respects, the JCPOA continues a tradition set by Cold War US presidents who negotiated with 'the evil empire' over nuclear arms in the knowledge that US-USSR competition would continue unabated elsewhere. These earlier presidents took a realist position, seeing things as they were and advancing US interests as they could rather than as they might wish. Trump is at odds with the traditional 'realist' US approach to negotiations which even Reagan followed.
But maybe this is all a bit of a red herring. The JCPOA may be an important issue in the Trump Administration's Iranian angst, but it is arguably not its most pressing. The war against Islamic State in Iraq is drawing to a close, but neither Iran nor the US want to go home and leave Iraq to the Iraqis. The most pressing issue seems to be that both Iran and the US want the other to leave.
Islamic State might be defeated in Iraq, but it is now deeply embedded in the US military psyche and the Republican party. Retired US Army generals (together with at least one retired Australian General) and the GOP are deeply convinced that Islamic State was able to comprehensively defeat the Iraqi army in 2014 only because the US had not maintained a strong military presence in the country. It has become a firm belief – not necessarily historically accurate – that Obama assisted Islamic State's success by being too eager to leave Iraq, rather than strong-arm the Iraqi government into allowing US forces to stay. Trump, of course, took this further by declaring that Obama (along with Hillary Clinton) founded Islamic State, a claim elements of Trump's base may be inclined to believe.
The problem for strategists, retired generals, the Trump Administration and the Republican-dominated US Congress now is that all this aggressive rhetoric makes US withdrawal from Iraq very problematic. In a sense, the US is now trapped in Iraq even after Islamic State is defeated. Some speak of up to 20,000 US troops remaining indefinitely.
From an Iranian viewpoint, the Islamic State invasion led to the return of US forces to Iraq, a renewed US influence over the Iraqi government and the replacement of a pro-Iranian leader by one approved of by the US. With Iraqi elections due in April next year, Iran is now assiduously working to reclaim its earlier political influence and, if possible, extend it.
Iranian influence did not just go into reverse during the Islamic State interregnum, however. The war allowed Iran to revitalise the Shia militias Iran created during the US occupation of Iraq as the Popular Military Forces (PMF). Iran seems to have hopes that at least parts of the PMF's 60,000 plus personnel will become an alternative military force to the Iraqi national army – duplicating the Iranian model, where the Islamic Revolutionary Guard Corps exists alongside the regular armed forces.
It seems unlikely the US and Iran will happily coexist in post-Islamic State Iraq, just as they could not during the US occupation. Instead, it is more probable that Iran (as before) will use various covert means, including proxy forces, to raise the costs in blood and treasure of the US staying. Some fret Iran has already commenced such a plan. On 1 October, an explosively formed penetrator (EFP) killed a US soldier and wounded another. Such devices were a signature weapon of the war and were supplied by Iran in large numbers to its proxies during the US occupation. EFPs are credited by US Central Command with killing nearly 200 US soldiers and wounding some 800 in the 2005-2011 period.
Iran may optimistically believe that a similar campaign will succeed again in encouraging the US to wind down its troop commitment. Iran may also consider that such a campaign would not draw a disproportionate US response, but such hubris could be mistaken.
The real wildcard for Iran in any renewed campaign to push the US out of Iraq may be blowback from its earlier effort against the US. Trump has appointed former generals James Mattis as Secretary of Defense, John Kelly as White House Chief of Staff and the still-serving HR McMaster as National Security Adviser. All were serving in Iraq as Iran-supported Shia militias killed hundreds of Americans and wounded thousands more.
For former Marines Mattis and Kelly, their experience in Iraq overlays an enduring Marine Corps dislike of Iran emanating from Iranian involvement in the 1983 suicide bombing in Lebanon that killed 220 Marines. In 2012, when asked to name the three gravest threats facing the US, Mattis answered 'Iran, Iran, Iran'. Asked again in 2017, Mattis said that still held. In 2016 Mattis declared that 'the Iranian regime, in my mind, is the single most enduring threat to stability and peace in the Middle East...nothing, I believe, is as serious in the long term'.
Regardless of whether the JCOPA continues or falls, the US and Iran appear set on another violent collision in Iraq and possibly across the Middle East. As a close US ally, Australia could become involved in any US actions to roll back Iranian influence. Australia already has a frigate semi-permanently deployed to the Arabian Gulf, an offensive air support force in the United Arab Emirates and an Army training unit and Special Forces in Iraq. Australian forces might get caught in any US-Iranian crossfire, purely by accident. However, although Iranian military units and personnel are spread out across Iraq and Syria, the Republican Guard Navy's speedboats which regularly harass the US Navy in the Gulf seem particularly vulnerable. It is here that the US may choose to flex its muscle, just as it did back in the 1980s.
Strategically, Australia would undoubtedly prefer America to focus on the Indo-Pacific region rather than become further embroiled in the Middle East. We may well be disappointed.