When the consequences of the United States-led invasion of Iraq ten years ago are fully assessed, the importance of the subsequent rise of political Islam there - and throughout the wider Middle East - may well pale in comparison to that of a geostrategic shift that no one foresaw at the time. That shift, however, has now come into view. With America approaching energy self-sufficiency, a US strategic disengagement from the region may become a reality.
The Middle East, of course, has experienced the withdrawal of a great power, or powers, many times before: the disintegration of the Ottoman Empire after World War I; the fraying of the French and British imperial mandates after World War II; and, most recently, the nearly complete disappearance of Russian influence following the collapse of the Soviet Union in 1991. Each time, monumental changes in the region's politics, particularly its alliances, quickly followed. If America attempts to wash its hands of the Middle East in the coming years, will a similar rupture be inevitable?
Although many believe that the US-Israel alliance is the foundation of America's Middle East policy, it was dependence on imported oil that motivated the US to establish a dominant military presence in the region after 1945. Indeed, until the Six Day War of June 1967, the US was not a major supplier of military hardware to Israel. America's military presence was intended, above all, to preserve the Arab status quo, and hence the flow of energy from the Arabian/Persian Gulf, for the benefit of the US, its allies, and the entire global economy.
Is oil the future of energy?
Of course, no one should think that America's shale-gas revolution (which has brought it to the brink of energy self-sufficiency) means that its Bahrain-based Fifth Fleet will lift anchor any time soon. But the rationale for America's commitment of military force to the region is changing fast; when that happens - as it has in Europe, for example, since the Cold War's end - the distribution of military assets tends to change as well.
That change is almost certain to be reflected in America's relationships with its Arab allies and partners. As the US statesman/academic Joseph Nye has argued: "For decades the United States and Saudi Arabia have had a balance of asymmetries in which we depended on them as the swing producer of oil and they depended on us for ultimate military security." Given America's burgeoning domestic energy supplies, Nye argues, those "bargains will be struck on somewhat better terms", at least from the US perspective.
But, whatever new terms are struck, the degree of US disengagement from the Middle East will depend on how two key questions are answered. First, would even a partial withdrawal of military force create a security vacuum that could be filled by a rival - say, China or Iran? And, second, would any diminution of America's commitment to the region incite the kind of instability that breeds failed states and terrorist havens?
President Barack Obama's current security strategy in Afghanistan, Yemen, and elsewhere suggests that the US will seek to mitigate the latter risk by continuing its covert interventions - particularly its use of unmanned aerial vehicles. Preventing rivals from gaining overweening influence in the region, however, will require a very different type of response - one that will require the backing of old allies, such as Japan, and new friends, like India.
The reason for this is clear: China's dependence on Middle East energy imports means that it is almost certain to seek to fill any regional security vacuum. Indeed, China appears to have long anticipated the coming changes in the region's security structure, and already seems prepared to take advantage of them if permitted to do so. Its "string of pearls" across the Indian Ocean - a series of potential naval stations connecting China to the Middle East and Africa - would support a Chinese blue-water navy able to patrol the sea-lanes of the Arabian/Persian Gulf.
But, in trying to strike new bargains with Middle East oil producers, China has already been compromised by its strong backing of Iran, which is locked in a power struggle with the region's leading Sunni states, particularly Saudi Arabia. Absent a complete shift in China's relations with Iran, a strategic partnership with the monarchies of the Arabian/Persian Gulf may prove impossible to achieve. And, even then, China's domestic repression of Xinjiang's Muslims, which provoked a fierce dispute with Turkish Prime Minister Recep Tayyip Erdogan just a few years ago, may preclude the necessary trust from ever taking root.
Still, China's inevitable bid for greater influence in the Middle East means that countries like India, Indonesia, Japan, South Korea, Turkey and others will also need to become proactive in creating a regional security structure that protects their national interests. They will need to be clear with themselves about whether they have the means to achieve their national security ends. For example, could they provide some of the security that America has long provided to the region's Arab states?
Such a projection of Asian power - and of Asia's power struggles - into the Middle East may seem a distant prospect today. But ten years ago, so did the possibility of an American disengagement from the region.
Yuriko Koike, Japan's former defence minister and national security adviser, was Chairwoman of Japan's Liberal Democrat Party and currently is a member of the National Diet.
A version of this article first appeared on Project Syndicate.
The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.