Most eyes may still be on Syria as the epicentre of global tension, but the temperature just rose in South China Sea too where several countries, including China, lay claim to the same waters.
The much-previewed US challenge to China's claims has finally taken place with an American navy warship sailing within 12 nautical miles of one of the artificial islands Beijing has built in the disputed waters of the Spratly, or Nansha, archipelago.
Chinese naval vessels shadowed the US ship and warned it off, but no clash took place - this time. China's navy commander has warned his counterpart of the danger of an accidental war if the Americans do it again.
The American move comes just a few weeks after President Obama gave President Xi the red carpet treatment in Washington. So what's going on?
The US was demonstrating that it doesn't recognise China's extensive claims in the South China Sea.
It also insists it doesn't take sides over Beijing's disputes with the Philippines, Vietnam, Malaysia, Indonesia and Brunei, which also claim parts of the Sea.
To try to substantiate this, the US patrol also passed through areas claimed by Hanoi and Manila, but as Washington has been distinctly quiet over the island-building activities of other countries, which pre-dated China's, it is clear the Americans are only really bothered by the Chinese.
The Pentagon characterised the patrol by the USS Lassen as "routine", but given the months of discussion and open hinting by Washington that it would carry out such a patrol, it clearly wasn't.
There are other inconsistencies in the US position too, although both Beijing and Washington are being disingenuous.
The Pentagon describes the patrol as a Freedom of Navigation exercise to demonstrate that its ships can sail wherever international law and customary practice allow.
But despite its extensive claims in the South China Sea, there is no evidence China is threatening that freedom. In fact, given the dependence of its economy on trade and energy imports passing through the Sea, it is not in Beijing's interest to do so.
By sailing close to one of China's artificial islands, the Americans were seeking to utilise one of the clauses of the international treaty governing use of the seas - UNCLOS, the UN Convention on the Law of the Sea.
The only problem is the US itself has never ratified UNCLOS.
If Washington is concerned about establishing the right of freedom of navigation for its ships, a more effective and consistent way to do it would be to push the Senate to ratify the treaty.
This patrol was less about international law than raw power. Everybody, including of course China, knows the US did it to show that it can and to show the Chinese it is still boss on the water to try to deter Beijing from consolidating its extensive claims in the region.
As for China, it is a party to UNCLOS, but its position is also flawed.
Beijing denounced the sail-by as "illegal", but under the Convention it wasn't.
China has also shown a lack of regard for UNCLOS by refusing to take part in arbitration with the Philippines under the Convention - a refusal that has not had the desired effect of preventing the Permanent Court of Arbitration from allowing the case to go ahead.
Chinese officials say Beijing has built the artificial islands - seven in the past year - to provide airfields and docking facilities to support disaster relief operations in the typhoon-prone region.
That is valid as far as it goes, but by asserting the 12-mile limit around these installations, China is also clearly using them to advance its territorial claims.
If it wants to uphold the international law it says is essential for maintaining peace, China should agree to talks to settle these claims by compromise as it has done on several of its land borders. Instead, it says it wants to agree a code of conduct to manage relations in the South China Sea with its South East Asian neighbours, but talks on that have yet to yield any fruit.
This has led to rising tensions, particularly between China and the Philippines and Vietnam, both of which have turned to Washington for support, giving the US another reason for its challenge to Chinese claims - to show its friends it can be relied on when push comes to shove.
Although, Chinese and American officers have been talking about ways of reducing the risk of accidental clashes on the sea and in the air, more is needed if the two sides want to avoid getting into a shooting war.
A better course would be for China to sit down with its rival claimants and settle their maritime borders - and for the US to leave them to it.
As things stand this is unlikely to happen.
China shows no appetite for multilateral talks and despite Washington's lip service to the changing global order, the US attempt to stop its allies joining Chinese-led initiatives, like the Asian Infrastructure Investment Bank, shows it has still not been able to truly accept that the rise of China means it has to treat Beijing as more of a military and diplomatic equal.
As much as anything else this is what lies behind the US Navy sail-by, which instead of encouraging compromise over the South China Sea, is only stoking further tension.