In a six-day span the U.S. State Department has bluntly affirmed unequivocal backing for Japanese territorial claims against both Russia and China, even invoking a defense treaty provision that could lead to direct military intervention and war with the world's most populous nation.
Beginning a 13-day, seven-nation tour of the Asia-Pacific region on October 27 in Hawaii, Secretary of State Hillary Clinton visited Joint Base Pearl Harbor-Hickam and met with Admiral Robert Willard, head of U.S. Pacific Command - the largest overseas regional military command in the world - and held a joint press conference with new Japanese Foreign Minister Seiji Maehara in Honolulu.
Clinton's comments on the occasion underlined Washington's increasingly assertive - and intrusive - role in East Asia and the Western Pacific Ocean. They included:
"This year, we celebrate the 50th anniversary of our alliance, which was forged at the height of the Cold War. At the time, President Eisenhower described the indestructible partnership between our two countries, and time has proven him right. The world's geopolitical landscape has shifted many times since then, but the partnership between the United States and Japan has endured....This alliance is the cornerstone of American strategic engagement in the Asia Pacific..... I'm grateful that we are the two largest contributors to reconstruction in Afghanistan." 
Responding to a question from the press corps on an East China Sea island chain contested by Japan and China - the Senkaku Islands in the Japanese designation and the Diaoyu Islands in the Chinese - near which a Chinese trawler collided with two Japanese coast guard ships on September 7, almost leading to an international incident, Clinton added that for the government she represents "the Senkakus fall within the scope of Article 5 of the 1960 U.S.-Japan Treaty of Mutual Cooperation and Security. This is part of the larger commitment that the United States has made to Japan's security. We consider the Japanese-U.S. alliance one of the most important alliance partnerships we have anywhere in the world and we are committed to our obligations to protect the Japanese." 
Clinton's raising Article 5 of the 1960 Treaty of Mutual Cooperation and Security between the United States and Japan, which states that "Each Party recognizes that an armed attack against either Party in the territories under the administration of Japan would be dangerous to its own peace and safety and declares that it would act to meet the common danger," paralleled and followed by three months a similar attempt to intervene against China in the South China Sea.
On July 23 Clinton spoke at the 17th Association of Southeast Asian Nations (ASEAN) Regional Forum in Hanoi, Vietnam, and alluding to disputes in the South China Sea between China and ASEAN member states Vietnam, Malaysia, the Philippines and Brunei over the Spratly Islands and between China and Vietnam over the Paracel Islands, she maintained that "The United States, like every nation, has a national interest in freedom of navigation, open access to Asia's maritime commons, and respect for international law in the South China Sea....We oppose the use or threat of force by any claimant."  Clinton had the temerity to evoke the United Nations Convention on the Law of the Sea, which the U.S. has not ratified.
Her allusion to the prospect of force being used is - could only be - a reference to China in the current context. In an indisputable attempt to take up cudgels in alleged defense of the ten members of ASEAN - Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar (Burma) the Philippines, Singapore, Thailand and Vietnam - against what is being promoted by Washington as a common threat, China, Clinton delivered the opening salvo in what has since been an intensifying campaign to introduce the U.S. as not so much a mediator as a power broker and military guarantor in the Asia-Pacific region.
An outside player whose main "negotiation" tools are U.S. Pacific Command and the world's largest expeditionary naval force, the U.S. Seventh Fleet, with 5060 warships, 350 aircraft and as many as 60,000 sailors and marines attached to it at any given time.
In her comments in the Vietnamese capital on July 23 Clinton foreshadowed the renewed American emphasis on East Asia, in particular on isolating and confronting "outposts of tyranny" (her predecessor Condoleezza Rice's term) Myanmar and North Korea and revivifying and expanding military alliances in the area. 
"The day before, I was in Seoul, my third visit to Korea as Secretary. Together, Secretary Gates and I have sent the strong message that 60 years after the outbreak of the Korean War the U.S.-Korea alliance is strong....I've just completed two days of intensive consultations with my ASEAN colleagues and with the other partners who have come here to pursue a common endeavor: strengthening security, prosperity, and opportunity across Asia....[T]he Obama Administration is committed to broad, deep, and sustained engagement in Asia." 
The Pentagon demonstrated what America's sustained engagement in Asia means starting two days after Clinton's statements in Vietnam and every month since: With the Invincible Spirit military exercise in the Sea of Japan/East Sea starting on July 25. The first joint U.S.-Vietnamese military exercise - naval drills in the South China Sea - and the Ulchi Freedom Guardian military exercises in South Korea in August. Anti-submarine warfare maneuvers in the Yellow Sea near where China claims an exclusive economic zone in September. Confirmation late last month that naval exercises will be held in the near future in the Yellow Sea with the participation of the almost 100,000-ton nuclear-powered supercarrier USS George Washington, based in Yokosuka, Japan, which was deployed for the earlier Sea of Japan/East Sea and South China Sea exercises.
During the same period, from late July until the present, U.S. Pacific Command and Central Command led multinational military exercises in the two countries aside from North Korea that border both Russia and China - Kazakhstan (Steppe Eagle) and Mongolia (Khaan Quest 2010)  - and in Cambodia (Angkor Sentinel) and the Philippines (Amphibious Landing Exercise 2011).  The U.S. also conducted this year's Rim of the Pacific (RIMPAC 2010) naval warfare exercises, the world's largest, off Hawaii from June 23 to July 30.