The South China Sea is a volatile place - or rather, its politics are.
China, Vietnam, Malaysia, Brunei, the Philippines and Taiwan have been fighting over this azure stretch of the Pacific for more than a century. But tensions increased markedly in recent years as China, claiming the South China Sea as its own, has built on and militarised some 250 islands off the coasts of Vietnam, the Philippines and Taiwan.
Meanwhile, the United States continues to insist that the sea remain under international control. Presidents Donald Trump and Xi Jinping were supposed to discuss the situation during their first meeting at Mar-a-Lago on April 5 2017. But the launch of 59 Tomahawks in Syria and growing tensions on the Korean peninsula completely overshadowed the maritime issue.
Two months after that meeting, the US triggered a classic confrontational cycle in the South China Sea. On May 24, the guided-missile destroyer USS Dewey passed through the contested waters and sailed close to Mischief Reef, in the Spratly archipelago.
The island, controlled by China, has become a symbol of the country's assertiveness since it was occupied in 1995.
The operation was the first military maritime exercise in eight months and the first of Trump's presidency. Under the Obama administration, starting in 2015, American patrols in the South China Sea were regular practice.
Freedom of navigation
The South China Sea Freedom of Navigation Operations (FONOPS) is a US military program, open to regional allies (such as Australia, Japan and the Philippines), in which the US leads maritime exercises in the area. FONOPS is aimed at reiterating the inalienable principle of freedom of navigation in international waters laid out in the United Nations Conventions on the Law of the Sea (UNCLOS).
China disputes this application of the UN declaration and perceives FONOPS as essentially a unilateral American endeavour. The Department of State asserts that the US can and will exercise its freedom of navigation on worldwide, without interference by any other country.
War ships, it has affirmed, should enjoy the same freedom as any other vessel, meaning free access to both exclusive economic zones (EEZ) and territorial seas without permission from the relevant coastal state.
China, which has also been in bilateral talks on the South China Sea with the Phillipines since early this year, has a different interpretation. For Beijing, military vessels cannot enter a coastal state's territorial seas without official permission.
It also claims that military ships in EEZ territorial waters are unlawful and suspicious, and only non-military vessels enjoy the right to passage.
The clash of unilaterality is clear, and both countries are firm in their stances. For the US, ensuring the freedom of navigation throughout Asia-Pacific region is a national prerogative and a matter of vital importance. As such, China - specifically, its military activities on some of the disputed South China Sea islands - is clearly its main obstacle.
A confrontation appears unavoidable, but, for now, interactions have cleverly been kept on a safe track, as no US allies have joined in the FONOPS exercises.
FONOPS is often misinterpreted as a challenge to China's claims in the South China Sea. In fact, the freedom of navigation operations are not explicitly aimed at questioning Chinese sovereignty in the South China Sea.
Why it's important for Trump's administration
Still, the US has a clear interest in preserving its role as a regional hegemon, and FONOPS could be seen as a provocation of Beijing and its divergent maritime stance.
During his first months in office, President Trump was accused of neglecting the South China Sea dispute and undervaluing the maritime routes encompassed in the Chinese Nine-Dash line. As the New York Times has reported, the Pentagon has on two occasions turned down requests by the US Pacific Command to conduct operations in the disputed waters, in February and April.
Trump's cabinet has given every sign that it will continue the South China Sea policy developed under the Obama administration. On February 4 2017, Secretary of State James Mattis reiterated the importance of the South China Sea on the American agenda. Several months later, Admiral Harry Harris assured that the FONOPS in the South China Sea were planned as usual.
Timing is key in the waltz between Washington and Beijing. The US needs China's support in facing a growing number of global challenges, from terrorism to North Korea. And with Trump already pushing China on trade, evidently his weapon of choice for addressing the nations' multifaceted bilateral relationship, the administration may have seen a strategic reason for waiting to pressure Beijing on the South China Sea.
By relaunching operations in the region in May, the US reassured its Asian allies about its continued presence there. China was able to underline its different approach and criticise the US for jeopardising regional peace, thus bringing this FONOPS cycle to a close.
Beijing is well aware that such operations will continue, of course, just as Washington knows how China will respond. Ultimately, FONOPS is a geopolitical balancing act: it does not pose a direct threat to the status quo, which is favourable to China. But it asserts the US' hegemonic role in the Asia Pacific.
Though competition between the two world powers will continue, it seems unlikely to escalate in the near future. Reciprocal accusation of undermining regional stability are, in the end, business as usual.