A man with a mask of U.S. President Barack Obama attends a protest against Obama's visit to Japan, in Tokyo, Japan, April 23, 2014. Obama arrived in Japan on a four-country trip through the Asia-Pacific region on Wednesday. [Xinhua photo]

U.S. President Barack Obama sits down with Japanese Prime Minister Shinzo Abe on Thursday for a summit widely expected to see the guest reassure its alliance with the host.

But the pomp and circumstance Obama receives as the first U.S. president to visit Japan as a state guest since Bill Clinton in 1996 cannot conceal the fact that Tokyo has become a growing liability to Washington's pursuit of long-term interests.

Increasingly flagrant on historical issues, assertive on territorial disputes and defiant of U.S. advice, Japan is hijacking its alliance with the United States and Washington's "rebalancing to Asia" policy to serve its own agenda.

Among these historical spats arising from Japan's war-time atrocities, 70 year ago in WWII, Japanese politicians are still frequenting the controversial Yasukuni Shrine.

After receiving Abe's ritual offering on Monday, the shrine -- honoring 14 Class-A WWII criminals alongside the country's war dead -- was visited by 146 Japanese lawmakers en masse one day later.

Not seeming to have the least intention of soothing the U.S.' "disappointment" or the outcry from neighboring countries over the visit, Abe has dismissed the idea of building a new memorial to replace the shrine, which he deliberately understated as a "venue for mourning."

The Asian status quo has also been severely challenged lately by Japan blatantly claiming sovereignty of China's Diaoyu Islands, and military flexing by breaking ground on a radar station on the western Yonaguni island Saturday -- a move that enables Japan to expand surveillance to near the Chinese mainland.

The Abe administration, more assertive about autonomy and less apologetic about the country's villainous past than predecessors, has become nothing but a negative asset to Obama's Asia rebalancing blueprint.

With all these dangerous and defiant moves, Japan's relations with almost all its neighbors and regional heavyweights have been soured, which by no means fits the U.S. strategic interests in the region.

For all these consequences, Tokyo should be fully accountable. Capricious and indocile as they are, the country's right-wing politicians should be reined in by Obama during his trip.

Also, the U.S. should reconsider the attempt to promise the protection of Japanese land in exchange for Tokyo's concession in the ongoing Trans-Pacific Partnership Agreement, which will further embolden Tokyo's recklessness in challenging regional peace and stability.

Obama is almost sure to walk a tightrope during his tour, since on the one hand he has to retain the thorny relations with a trouble-making ally, while on the other he has to appease other Asian nations. This includes key regional partners like South Korea, which have complained about U.S. acquiescence to the crotchety and defiant Japanese government.

Also, before giving any commitment to Japan, Obama should be mindful of China's core national interests, which he has promised to respect when outlining the "new type of major-country relations" with his Chinese counterpart Xi Jinping last June.

It's time for Washington policy-makers to realize that in an age of closer Sino-U.S cooperation, Tokyo's geopolitical significance in the region will be further reduced.