Since the map of the Middle East was drawn by the Sykes-Picot Agreement in the aftermath of World War I and the retreat of the Ottoman Turks in favour of the British and French, the lines demarcating the boundaries between states in the Arab region have never been successfully challenged, even in the heyday of pan-Arab nationalism.

Saddam Hussein's ill-conceived adventure in neighbouring Kuwait ended in catastrophe, costing him his regime, and eventually, his life. But two decades later, a small obscure group has, ironically, managed to achieve what the once mighty Iraqi army had failed to do in 1990. Declaring its dominance over huge swaths of land in Iraq and Syria, ISIL has effectively erased the long established frontier between the two countries, thus mounting the first successful challenge to the Sykes-Picot arrangement.

History abounds with shadowy extremist organisations, centred on deviant ideas - not always of a religious nature - eccentric megalomaniacs, or purely criminal objectives. ISIL is neither unique nor without precedent in this respect. What distinguishes the group is in reality neither its fanaticism, nor brutal methods, but the suddenness of its rise and astonishing speed of its territorial expansion. In the space of a few months, this once marginal faction has come to occupy the centre stage of international politics, threatening the existence of entire regional states and governments, redefining old political geographies, even managing to bring together sworn enemies around the shared goal of defeating it, from Iran and Qatar to the US and Gulf kingdoms.

Unexpected ascendancy



Endlessly churned out epithets about ISIL's theological origins, exclusionary takfiri (apostate) tendencies and religious legitimisation of its brutal methods are useless in the quest to grasp the causes of its unexpected ascendancy and rapid proliferation.

It is the changing geopolitics of the region that holds the answers here. What gave and continues to grant ISIL - and other violent anarchic groups of its kind - momentum and room for diffusion is the strategic and political vacuum generated by the retreat of US influence in the Middle East, and Arab Orient more specifically.

The US is no longer able to monitor and regulate the rhythm of events in that sensitive part of the world. The wave of exhibitionist pre-emptive strikes launched by the neo-cons ended in two consecutive military defeats and hasty retreats.

The limits of US military might were laid bare for all to see. Thanks to its superior firepower, it was able to topple regimes and dismantle existing structures, but was dismally impotent to rebuild them anew. And in the vacuum and trail of devastation it left behind, the US created a fertile soil for the growth of extremist violent groups, on the one hand, and of internecine ethnic and sectarian conflicts, on the other.

Another irony is that the Americans find themselves today compelled to return to the Middle East, having retreated from it in order to channel what remains of their might on the escalating threat posed by a rising China and respond to the challenges of the shift of wealth and influence eastwards. But Obama's US looks nothing like the one that had mobilised its fleets against Saddam Hussein a decade ago. Today, it reluctantly retraces its footsteps to the same battlefield, broken and bruised, full of caution and foreboding.

The geopolitical void that appeared with the decline of US power after Afghanistan and Iraq was further exposed with the Syrian revolution, as the US and its Gulf allies proved powerless to end the conflict conclusively in their favour, desperately jostling for control and influence with the Iranians and the Russians. And as in Iraq, radical jihadist groups swiftly moved in to fill the resulting political vacuum, finding an ideal social foster in long standing sectarian grievances.

Complex demographics



Today, we are witnessing the explosion of the complex demographics of Arab society. In colonial times, local administrations had managed tensions between its myriad traditional social configurations, religious, sectarian, tribal, and ethnic, via a policy of containment, dilution, or repression. This role was subsequently taken up by the post-colonial state within a process of superimposed pseudo-modernisation, and under the banner of a collective national identity that remained feeble and skin-deep.

Amidst the collapse of fragile post-colonial political structures in countries like Libya, Iraq, Syria, and Yemen, traditional bonds and identities have reasserted themselves again, but in a more raucous bloody manner. Sunnis, Shia, Kurds, Arabs, Muslims, and Christians, all turned against each other in a chilling spectacle of senseless self-mutilation.

This atmosphere of paranoid animosity, social disarray and political crisis was a potent incubator for Islamic radicalism, with its ideological fervour, excommunicatory tendencies, and puritanical dreams. Political grievances mingled with ethnic and sectarian grudges to produce the hatred ridden grandiose discourse of al-Qaeda, ISIL and their Jihadist likes.

Price of failure



Today, the region is paying the price for the failure of top-down modernisation and the disintegration of artificial post-colonial national borders and frail political edifices. And with the evaporation of the great hopes pinned on the Arab Spring of the possibility of change through peaceful means and popular protests, extremism and violence have reared their head once more. But as disillusionment and despair descend on the region and tighten their icy grip on its throat, this deformed ghoulish child of crisis looks uglier, deadlier and more vindictive than ever.

By renewing and bolstering old alliances with Gulf sheikhdoms and autocratic Arab regimes to thwart democratic political change; overseeing the return to military coups and cloaking them with legitimacy, the US and its European allies have sent Arabs a clear resounding message: "Ballot boxes are not for you! They are pointless as means of change. Their results are easily discarded and trampled upon. Violence and revenge are the way out of your bleak existence." Nothing could have rendered more credence and legitimacy to the rhetoric of ISIL and the jihadist cause.

Through its modern history, the Arab region has been an open index of the ascent and descent of global powers and a mirror of the great players' fluctuating fortunes. And in this strategically positioned part of the globe, power shifts have always come at a heavy price, paid in much blood and socio-political instability, be that from the Ottomans to the British in the wake of the World War I, or to their American heirs after World War II. The currently unfolding transformation is no exception. The wave of turmoil, chaos and misery it carries will most likely continue to engulf the region for years to come.

Soumaya Ghannoushi is a British Tunisian writer and specialist in Middle East politics. Her articles have been published in the Guardian, the Independent, Corriere della Serra and Alquds.