Those selling the war against ISIS are likely to point out what is new about the present crisis. First and foremost, they will say, the character of the enemy is no longer a conventional sovereign state but a jihadist group that claims to have set up a caliphate called 'the Islamic State'. And on this occasion, they add, military assistance has been requested by the host government.
Despite these apparent differences, it would be misguided to think that what is unfolding now can be made intelligible without reference to the idea of an Iraq War that has been waged across a quarter of a century.
This long war has had three incarnations, or at least, this is how standard accounts of intervention would conceive of it. The first version (1990-1991) was an instance of UN-led collective security action to liberate Kuwait. The 2nd episode (2003) was a war of regime change, and the third is the war against the Islamic State.
What then, are the convergent dimensions of the long war?
The first is the recurring theme of a war for civilization against barbarism. Following the annexing of a neighbouring state in 1990, Saddam Hussein was characterised as an international pariah who threatened the entire system of independent sovereign states.
By 2002-2003, this language of friend/enemy was taken to new heights after the attacks of 9/11. In his 2002 State of the Union Address, George W Bush singled out Iraq for the brutal treatment of its own citizens, pursuit of weapons of mass destruction and support for terrorist organisations.
In debates about the nature of the threat from the Islamic State, little mention has been made of preserving the UN Charter System. Instead, the focus has been on the barbarity of the public beheadings, and how such 'evil' (to use UK Prime Minister Cameron's characterisation) must be eradicated. Those of 'us' who join their fight, argues Prime Minister Abbott, are against 'God' and 'religion'.
The second connecting thread concerns the vexing question of the legality of force. For the last 25 years, the UN Security Council, the body charged with maintaining international peace and security, has been more of a spectator than a player.
In the case of the imposition of no-fly zones over northern Iraq in April 1991, the intervening Western states argued that Resolution 688 provided sufficient legal justification. In truth, this resolution did not authorise force. Had the the US, UK and France pushed for 'all necessary means' to protect the Kurds, they would not have received support from the other 12 members of the Council.
Nor did the Security Council give the US what it wanted in 2002-03, even after intense negotiations in New York. The level of discord extended far beyond the Security Council, as the 116 states that constitute the Non-Aligned Movement of the UN General Assembly called for a peaceful settlement to the crisis and voiced concern about the need to avoid double standards.
The third incarnation of the long war in Iraq has so far achieved greater diplomatic consensus, unsurprising given how the Islamic State's executions have caught the public's attention. Several Arab states including the UAE and Saudi Arabia have offered to assist with the campaign.
Yet thus far, the talk has been about building an ad hoc coalition of the willing rather than obtaining a clear legal resolution in the Security Council. Interestingly, Obama and other leaders have shied away from characterising this intervention as war. Last week, Attorney General George Brandis denied Australia was at war, labeling its involvement a 'humanitarian mission with military elements'.
Finally, what to make of the links between national security and humanitarian arguments that finds resonances in all three episodes of the long war? The limited war aims of the 1990s intervention altered when there was an outcry about the massacre of Kurds in the north and Shia in the south.
In 2003, the doctrine of preventive war wove together two threads: a national security imperative and a humanitarian crusade. Obama has similarly coupled these issues in his early framing of the current crisis.
President Obama's 10 September address to the nation emphasised a need to 'degrade and ultimately destroy ISIS'. Yet in stark contrast to the inflated threat assessments made by the UK government with respect to Saddam Hussein's alleged WMD capability in late 2002, Obama was unwilling to represent Islamic State as a threat to the 'homeland'. In Obama's words, 'that's not what this is about'.
Claims that the war against ISIS is a novel war, against a new threat, with new aims obscure as much about the present as they do about the recent past. Indeed, much of this rhetoric stems from governments that have been involved, in one way or another, in each major campaign since 1990: the US, UK, and Australia (and France, except for 2003).
Each campaign has been couched as an exception to the rule requiring extraordinary measures to counter the threat. Each campaign has counterposed the forces of civilization and barbarism. Each campaign has produced endings which later turn into periods in which the intensity of violence has lessened, only to escalate again as the long war continues.
Photo courtesy of Flickr user The US Army.