In Europe, Russia's seizure of Crimea from Ukraine last year represented the first forcible annexation of territory on the continent since the end of the second world war. Unsurprisingly, the Baltic states, which were once part of the Soviet Union, are very worried by the precedent - hence NATO's decision to reinforce its military presence there.

In Asia, China's island-building programme in the South China Sea has taken shape in the past year, transforming Beijing's theoretical claim to territorial waters thousands of miles from its coast into something that is (literally) more concrete. America says it takes no position on China's territorial disputes with its neighbours but that it is determined to protect freedom of navigation in the Pacific. Hence the US Navy's apparent decision to challenge the idea that China has established territorial waters around its new artificial islands.

All three disputes are a reminder that, despite voguish talk of a "borderless world", the control of territory is still fundamental to world politics. As Sir Robert Cooper, a former British diplomat puts it: "World orders are territorial orders. If you don't know who owns territory, you don't know anything about international order." Thomas Wright of the Brookings Institution makes a similar point when he argues that international political stability is dependent on "healthy regional orders, especially in Europe and east Asia. If these regions fall apart, nothing will save the global order."

Europe and east Asia are not "falling apart" but they are fraying at the edges. Meanwhile, the vision of a Middle East that really is falling apart is further unsettling both Europe and Asia by raising questions about US power and the durability of international borders. Even some American strategists who have long argued the US should "rebalance" its foreign policy towards Asia and do less in the Middle East are now having second thoughts, believing that a perception of US retreat in the Middle East is undermining US prestige in Asia.

The administration of Barack Obama is under pressure, at home and abroad, to restore the image of American strength by responding more forcefully to these territorial challenges. Decisions to send ships through waters claimed by China, and to deploy troops to the Baltics, are a response to that pressure. But Mr Obama remains well aware of the counterproductive nature of recent US military interventions in Iraq and Libya - and is also properly cautious about the risks of military confrontation with Russia or China.

The picture is further complicated by a dispute over who is the "revisionist" power in world politics. The US sees Russian and Chinese territorial claims as challenges to the world order. But the Russians claim that it is America that is truly undermining global order by sponsoring "regime change" in countries such as Ukraine and Syria.

There is an element of propaganda in Russia's claims. But both Beijing and Moscow also seem genuinely to fear that, unless they push back against US power, they too might ultimately fall victim to American-backed regime change. The Americans, for their part, worry that if they allow territorial revisionism to proliferate, the world will become a more anarchic and dangerous place as their global power erodes.

Mix these fears together and you have a recipe for the kind of dangerous regional disputes that are breaking out all over the world.

Financial Times