BEIJING, April 21-- Japanese Prime Minister Shinzo Abe on Monday made a ritual offering to the controversial Yasukuni Shrine in yet another provocative move detrimental to regional stability.

With U.S. President Barack Obama set to arrive in Japan on Wednesday for a three-day visit, Abe's donation is nothing short of a slap in the face of the leader of Japan's closest ally.

Abe surely understands that. Less than four months ago, his visit to the shrine not only infuriated China and South Korea, but prompted Washington to express explicit disappointment and urge Tokyo to mend ties with its neighbors.

Yet he and a handful of other senior Japanese politicians still stick to historical denialism and continue to steer their country down a rightist path reminiscent of militarism, which would inevitably further strain Tokyo's relations with Beijing and Seoul.

With both Japan and South Korea being important U.S. allies and China a global heavyweight with which the United States has committed itself to building a new type of major-country relations, Abe's apparently incorrigible trouble-making poses a real threat to U.S. interests.

The United States itself was a victim of the havoc fascist Japan wreaked during World War II. So it is imperative that Washington join the international community in condemning Abe's wrongdoing and preventing Japan from falling down the abyss of self-destruction again.

More importantly, it needs to reconsider its Japan policy, which has for years featured unprincipled support for an undisciplined ally at the cost of the overall interests of both itself and the region.

That is unsustainable. During his upcoming visit, Obama should send a clear message to Tokyo that the United States is no spoiler of repeated troublemakers and that Japan must learn and behave.