Beijing has been stoking the fires of Chinese nationalism recently, precipitating one diplomatic crisis after another. In the process, it has called into question whether China remains committed to pursuing its self-proclaimed "peaceful rise."

Last month, Beijing passed a militant "anti-secession" law directed at Taiwan. The action came just before the European Union was poised to lift its arms embargo against China. Beijing's move cooled E.U.-Chinese relations precipitously, leading Brussels to postpone any final decision to end the embargo.

In its latest attempt at "peaceful development," China is hectoring Japan over everything from history books to U.N. gamesmanship, plunging relations to their lowest point since the two re-established ties in 1972.

The latest rift is over the publication of Japan's newly-revised history textbooks. China claims they gloss over Japanese abuses during the 1931-1945 occupation. Beijing believes Tokyo hasn't properly "atoned" for the war.

The textbook release set off massive (Chinese government-choreographed) protests that included attacks on Japanese diplomatic facilities and businesses. Despite widespread vandalism, Chinese police arrested no one.

Long standing territorial disputes are erupting, as well. Both Tokyo and Beijing claim a string of islands in the East China Sea, known as the Senkaku (in Japanese) or the Diaoyutai (in Chinese.)

Though uninhabited, the islands are thought to shelter significant undersea gas (and possibly oil) reserves. With China and Japan being the world's second and fourth largest consumers of energy, control of this chain is a huge deal for both.

The U.S. returned the islands to Japan, along with Okinawa, in 1972. Despite Japanese complaints, China began drilling near the islands last year. Last November a Chinese sub was also discovered in the area, within Japan's exclusive economic zone.

The situation worsened last week after Tokyo decided to retaliate, allowing Japanese companies to begin exploration in the same gas fields. Not surprisingly, Beijing denounced the move as a "serious provocation."

China's increasing anti-Japanese sentiments have spilled over into U.N. matters, too. Beijing rejected any Japanese bid for a U.N. Security Council (UNSC) seat under recently proposed reforms of the international body.

As a UNSC permanent member with veto rights, Beijing's opposition would block a Japanese bid. While supporting India, Germany and Brazil, China claims that Japan, the U.N.'s second largest donor, doesn't have the "moral qualifications" for a seat.

China's military buildup is also spurring an Asian arms race, pushing "pacifist" Japan to reconsider its defense policy. Many of the over 750 Chinese missiles now aimed at Taiwan are capable of reaching Japan (and American forces stationed there) as well.

Persistent rumors that the French will sell China Mirage fighters with advanced air-to-air missiles, and maritime patrol aircraft (if the E.U. arms embargo is lifted) has gotten Tokyo's (and Taipei's) rapt attention.

Japan and China will likely manage these issues in the short-term; Japan's foreign minister was in Beijing yesterday for talks. But the growing rivalry is only likely to get worse. And that would undermine regional stability - and American interests.

For starters, China might not pressure its ally, North Korea, back to the nuclear negotiating table. Beijing knows well Tokyo's anxiety about Pyongyang's nuclear weapon and ballistic missile programs.

Second, as political relations with Japan deteriorate, China is likely to accelerate its military buildup, especially its ocean-going navy. This would further ratchet up tensions with Taiwan and Japan - and the U.S., which has defense commitments to both Taipei and Tokyo.

Third, China's belligerence may well force Tokyo and Taipei into each other's embrace, forming a "virtual alliance" against Beijing. This won't settle well with China at all, which considers Taiwan a "renegade province."

Washington should be deeply concerned about the growing Tokyo-Beijing rivalry. The U.S. and China just established a high-level "Global Dialogue," and when they meet, Washington must clearly register its concerns with Beijing about the prospects of Chinese adventurism or miscalculation in the region. The U.S. must also caution China that we will stand behind our Japanese ally.

Peter Brookes, a former deputy assistant secretary of defense, is a senior fellow at The Heritage Foundation and a New York Post columnist.