Just two days before US President Barack Obama's visit to Japan on his four-nation tour of Asia, Japanese Prime Minister Shinzo Abe sent a ritual offering to Yasukuni Shrine, a symbol of Japan's past militarist past which honors 14 Class-A war criminals. On Tuesday, 146 Japanese lawmakers visited the shrine again. A couple of days before that (April 19, to be precise), Japanese Defense Minister Itsunori Onodera attended a ceremony to begin construction of a radar base on Yonaguni Island, just 150 km from China's Diaoyu Islands.

The three moves are the latest in a series of provocative actions taken by Japan that have escalated tensions with its neighbors, especially China and the Republic of Korea, over territorial disputes. Irrespective of whether he chooses to be a neutral mediator eager to ease the tensions or a supporter of Japan, Obama's role will be vital to the stability and political balance in East Asian.

Although US-Japan ties are critical to the strategic structure of the Asian-Pacific region since both countries are powerful in their own ways, Tokyo has been questioning the dominant role of Washington in the relationship by taking frequent actions to prove its importance. For instance, both countries still disagree over tariff and auto safety standards in the Trans-Pacific Partnership negotiations, something which Obama has promised to address during his visit to Japan.

More importantly, the US should be aware of the potential military threat that Japan poses to other countries in the region and take upon itself the responsibility of eliminating them because it is supposed to guide postwar Japan's policies. Judging from what Abe has done over the past year, his aggressive military moves make Japan's self-proclaimed "active pacifism" sound less convincing.

The fact is that Japan has kept on increasing its annual defense (rather military) budget. It has also been trying to acquire the right to collective self-defense, something that international treaties deny the former Axis powers for fear that they would amass weapons again and start another devastating war.

On one hand, Abe has repeatedly played up the "China threat" theory to win the support of Japan's allies. On the other, he has been urging the US to grant Japan the status of a "normal" country and end the postwar "discrimination" against it. The problem is that the Japanese interpretation of a "normal country" includes lifting the self-imposed ban on exercising the right to collective self-defense, which is something the international community will never accept.