Another coalition of the willing? It's probably the only way to stop IS.

In the world of realpolitik, your enemy’s enemy is, of course, your friend.

Funny to think that we’re now best of buddies with President Assad in Syria, because his murderous regime – although reprehensible – has decided to get stuck into the fight against the self-styled Islamic State. We hate these fundamentalists more than we hate the smartly-dressed Syrian strongman, although ironically the growth of ISIS was actually fuelled by our lack of willingness to support the more legitimate opposition to Assad’s authoritarian regime.

If you’re confused, it’s not really that surprising. The shifts of allegiance in the turbulent landscape of 2014 have all the hallmarks of an Orwellian dystopia. One day, Oceania is at war with Eurasia. The next, it’s in alliance with Eurasia to defeat Eastasia.

Politicians such as David Cameron are not really cut out for the international challenges faced by the UK in 2014. The British Prime Minister's politics are shaped by the bluster that comes with privilege and are completely lacking in substance. Platitudes on the economy and immigration are one thing. But when it comes to major international threats, he seems very lightweight in comparison with his immediate predecessors.

President Obama has more of an idea of the threats and a better sense of what is needed to tackle them, but is caught in an impossible situation. The American public’s appetite for military intervention is understandably at rock bottom and he’s forced to couch any justification for action in terms of US national interests. When he first authorised airstrikes against Islamic State fighters in northern Iraq, it was ostensibly to protect American diplomats in the city of Irbil. Stopping the genocide of the Yazidis was presented as a nice bonus.

The barbaric execution of US journalist James Foley might possibly be a game changer, but there are many limitations on what we can reasonably expect Obama to do. Wouldn’t it be so much easier if Islamic State could be turned back by the Kurdish Peshmerga fighters? We can pretend that all they need are some American and European arms and a few token airstrikes, but any gains will be short-lived. Islamic State will continue to expand to fill the vacuum that exists in Iraq and capitalise on the chaos that prevails in Syria. As they gain in confidence, they will try to destabilise Lebanon and Jordan.

It could be argued that there was only one bigger mistake than sending British and American troops into Iraq in 2003 and that was to take them away. The sectarian Shiite leadership in Baghdad has been hopelessly incompetent and managed through its deliberate actions to alienate large sections of the Sunni population. It’s this discontent which acts as oxygen for Islamic State as it charges through the region.

IS will not be stopped until it is confronted by a superior military force. There are really only three candidates.

The first is Iran, which will probably act if it looks as if the whole of Iraq is under threat and Shiite holy sites are being destroyed. The sectarian conflict which might ensue would be disastrous.

The second is Israel. Although preoccupied by its bloody conflict with the Sunni militants of Hamas in Gaza (and the latent threat of the Iranian-backed Shiites in Lebanon’s Hezbollah), Israel is well aware of the potential dangers posed by ISIS. The long-term objective of the most fanatical supporters of the ‘Caliphate’ is, after all, to head to Jerusalem. I doubt very much that Israel will act until such time as they perceive a very direct threat, but they will be watching developments closely.

The third option is a coalition of the willing, ideally under the auspices of the United Nations. In most instances, it’s very difficult to imagine any unanimity among the permanent members of the Security Council. Relations with Russia are at an all-time low because of the situation in Ukraine. But the fanaticism of Islamic State is anathema to Moscow, which has had its own issues with Islamic fundamentalism. China has faced terrorism from alienated Muslim minorities and, perhaps more significantly, has extensive economic interests in the Middle East and Africa.

Could it be that the threat posed by Islamic State is the one thing on which all the major powers might actually agree? It's possible that with time, people will come together. But time is the one thing we probably lack.