Diaoyu Islands in the E China Sea Photo: Xinhua

During a press briefing on Tuesday, Pentagon Press Secretary John F. Kirby, when addressing the issue of the Diaoyu Islands (what the US and Japan refer to as Senkakus), said, "We support Japan obviously in that sovereignty and we would urge the Chinese to avoid actions, using their Coast Guard vessels, that could lead to miscalculation and potential physical, if not - and material harm."

Japanese media outlets have paid extensive attention to Kirby's narratives. For example, Kyodo News headlines like: US raps China on activities near Senkakus, says it supports Japan.

However, judging from Kirby's context, his rhetoric over the Diaoyu Islands was still ambiguous. He did not clarify it as "support" toward Japan's claim over its "sovereignty" of Diaoyu Islands. But it's worth noting that although his narrative was not particularly clear, it was still a step forward from the US' prior vague position over the Diaoyu Islands.

Tokyo has been clearly aware that Washington needs its support to the Free and Open Indo-Pacific (FOIP) strategy. As a result, Japan hopes the US could make a clearer statement to back up Japan's claim on sovereignty over the Diaoyu Islands. To Japan's disappointment, Washington tends to be ambiguous on this issue.

Kirby's words on Tuesday were in a bid to show Japan the US' stance over intensifying its alliance with Japan. Washington hopes Tokyo can understand them as the US supports Japan over the issue of the Diaoyu Islands, so that Japan will side with the US to counter China and prevent China's further maritime development.

In recent years, at least during the Trump administration, the US has seen China as its major rival, trying to seduce every possible country to its anti-China crusade. As a pivotal ally in Asia, Japan must be one of the targets. To win Japan's support, the US has to make concessions on one of Japan's most concerning issues, the Diaoyu Islands.

During his first phone call with his Japanese counterpart Kitamura Shigeru, the new US Secretary of Defense, Lloyd Austin, confirmed that Article 5 of the US-Japan security treaty covers the Diaoyu Islands. US President Joe Biden also reaffirmed it in his first call with Japanese Prime Minister Yoshihide Suga.

Japan has been worried that Biden will seek to mitigate US tensions with China. In that scenario, the Biden administration's China policy will not be as tough as its predecessors in stance on containing China and will roll back the support to Japan's territorial claims over the Diaoyu Islands.

As a result, the Suga administration hopes Washington can deliver a clearer stance over this issue, to make Japan secure, and to prevent China from resorting to force to address their disputes.

In addition, the Biden administration also has its own calculations by repeatedly reaffirming its position over the disputed waters. First, by doing so, Washington can effectively strengthen its alliance with Tokyo while it becomes more determined to follow the US' crusade.

Second, it wants to show its tough position over China to please anti-China forces at home. Many of them believe that, in order to alleviate China-US tensions, the Biden administration will deteriorate the US relationship with some of its allies instead. 

Last but most importantly, Washington hopes to send a signal to Beijing, warning China not to take any radical or extreme measures on the Diaoyu Islands, as the US believes China has been increasingly "aggressive," including in maritime development. 

Actually, in terms of the territorial dispute, China's position has always been clear; the Diaoyu Islands belong to China and China insists on resolving the dispute by peaceful means. If the US and Japan continue to make further provocations on the Diaoyu Islands issue, China will certainly respond in a tougher manner. However, this is not what China expects to see. The escalation of regional tensions is not conductive to good bilateral relations between China and Japan or China and the US. It is also detrimental to regional security.

However, the Biden administration's policy over the Diaoyu Islands will primarily depend on the evolution of China-US relations. As long as both parties relieve tensions on their bilateral relations, the Biden administration will unlikely take any drastic and provocative policy and the regional security will be assured.

The author is deputy director of the Center for American Studies at Fudan University. opinion@globaltimes.com.cn