How dangerous is the Islamic State (IS)? Given the barbarism, ruthlessness and brutality of the IS in establishing a caliphate, in part by absorbing or coercing acceptance by Sunnis, Baathists and former Saddam loyalists disenfranchised or persecuted by the Shia government in Baghdad, will that amalgam hold? Or will IS’s inhuman behaviour ultimately provoke a rebellion by local Sunni tribes? Alternatively, is the IS phenomenon and the surprising suddenness of its seizure of space in Iraq and Syria a harbinger of an even greater threat to the region and beyond? Reports of IS now extending its poisonous tentacles into Pakistan may or may not prove accurate. However, the possibility is very worrying. The crucial question is whether IS is an existential danger over time or whether its threat has been exaggerated by its surprising successes so far in Iraq and Syria. History offers several interesting perspectives although the past is never a guarantee or even an accurate predictor of the future. Consider the Bolsheviks, the Nazis and the Chinese Communists. Vladimir Lenin was sent in a sealed train to Russia by Germany in April 1917, ultimately to engineer a separate peace that would end Russia’s role in World War I. Lenin, of course, did more than that. The subsequent revolution overthrew the Kerensky government and led the Bolsheviks to power by early 1918. Lenin’s tactics were to mobilise the few, armed with a powerful organisation, ideology, commitment and action plan that produced a takeover. While Adolph Hitler entered office as chancellor legally and then won elections in 1933, the Nazi Party likewise was well organised, ideologically committed to a doctrine of inhuman proportion and motivated by Germany’s defeat in World War I and the economic collapse that impoverished the state. Hitler then killed or imprisoned the opposition over his tyrannical and brutal rule. Similarly, Mao Ze Dong led the ideologically hardened, highly disciplined Communist Party of China in a decades’ long battle against the Japanese and Chiang Kai Shek’s Kuomingdong Party. Mao’s rule was often brutal in the extreme with millions of Chinese perishing from famine, the Great Leap Forward and the Great Proletarian Cultural Revolution imposed to replant Mao’s control. Of course, literally thousands of revolutionary and terrorist organisations have unsuccessfully attempted to win control of a state. But terror has also worked. One can argue that the Urgun and Palmach regimes of terror in Palestine against the British after World War II were critical of the creation of Israel. And just after World War I, rebellion in Iraq forced the British army to withdraw and the royal air force deputised to assume the role of imposing the will of the occupying power by applying punishment and retaliation from the air against the local forces. The IS, led by Abu Bakr al-Baghdadi, who established a caliphate earlier this year in Syria and Iraq, has taken some of its military tactics from the German Blitzkrieg. The IS struck quickly in gaining and controlling territory. Then, it followed up by assuming the role of local governance through a combination of extreme intimidation by crucifying or beheading anyone standing in their way and recruiting Sunnis, as noted above. At this point, the IS gains in Iraq are theoretically reversible. But that requires a political solution with genuine reconciliation among Shia, Sunni and Kurds, and a revitalisation of Iraqi security forces. That said, a basically Shia security force will have tough going in Anbar province, reportedly just captured by the IS. If the IS increases its hold over Iraq and mounts a successful assault against Baghdad, it will indeed become a potentially existential threat to the region and beyond. Saudi Arabia will be next on the IS game plan. Other regional states will become highly vulnerable. And the large number of foreign jihadists with legitimate European, African and US passports will constitute a clear and present danger to those regions. The coalition must focus on the potential consequences of the IS overwhelming the Iraqi government. A high-level coalition conference with heads of state and government is needed now. The first requirement is to cajole, convince or coerce the Baghdad government to move urgently in reconciliation. Then, the coalition must agree on what political and military support it will provide. Iran cannot be precluded even if engaged by cutouts. The threat of the IS may be exaggerated. But if effective action is not taken now, the IS will become existential. And that threat will extend far beyond the Middle East. The writer is chairman of the Killowen Group that advises leaders of government and business and senior advisor at Washington DC’s Atlantic Council. His latest book, due out this fall, is A Handful of Bullets: How the Murder of an Archduke a Century Ago Still Menaces Peace Today