The US Senate passed an amendment to the national defense authorization bill for 2013 on Thursday, stressing Washington's right to navigate freely in the East China Sea, which, it said, was an inalienable part of Asia's maritime interests.

The amendment, which is yet to be approved by the US House of Representatives and signed by President Barack Obama, puts China's Diaoyu Islands under the purview of a US-Japan security treaty. Despite the US saying that it will not support either China or Japan in the dispute over the Diaoyu Islands, the amendment says the US acknowledges that the islands have been under Japan's administration and unilateral action from a third party will not influence its stance. It also reaffirms Washington's security commitment to Tokyo as stipulated in the US-Japan security pact.

The passing of the amendment once again exposes the disgraceful role the US has played in escalating Sino-Japanese tensions.

The dispute over the Diaoyu Islands has pushed Sino-Japanese relations to their lowest since the normalization of their diplomatic ties in 1972. A lingering strain in Sino-Japanese relations will not only be detrimental to the security, stability, peace and prosperity of Northeast Asia, but also hurt the global economic recovery.

Responsible countries and politicians are expected to promote reconciliation and stability in Sino-Japanese ties. Regrettably, the US, which as the world's sole superpower has time and again told other countries to act responsibly, has done exactly the opposite by helping escalate Sino-Japanese tensions.

The move by the US Senate will inevitably embolden rightist forces in Japan to take further actions challenging China's sovereignty over the Diaoyu Islands and fan bilateral tensions, which the US thinks will help it realize its geopolitical goal of "maintaining a divided East Asia".

However, in the long run facts will prove that the US Senate has once again made a foolhardy decision. It is possible that the US' shortsighted move will exert some pressure on China, but in the end it will compromise the interests of the US.