According to China's Global Times, "The Russia-Japan row over the islands coincides with a dispute between Japan and China over the Diaoyu Islands in the East China Sea following Japan's detention of a Chinese boat captain in September....[T]he strong message by Medvedev's visit to the island, to some extent, echoes China's firm stance on its dispute with Japan." 
U.S. backing for Japanese claims on the Kurils has now progressed from tacit to explicit commitment, part of a policy of World War Two revisionism also evident in Washington's actions in Eastern Europe from the Baltic Sea to the Balkans which aim at undoing the results of the Yalta and Potsdam conferences and the entire post-war system of international relations.
After the break-up of the Soviet Union and during Russia's debilitated state under the Boris Yeltsin presidency in the 1990s, the first moves were made to do to Russia what had been done to the Soviet Union: Fragment it. From the Kuril Islands to the North Caucasus, from the Arctic to Kaliningrad and the Republic of Karelia, parts of post-Soviet Russia were coveted by neighboring states or otherwise targeted to be wrested from the country.
Japanese claims, though, have been even more brazen in recent years. In July of 2008 the Japanese government published new textbook guidelines directing teachers to instruct students that Japan has sovereignty over the Kuril Islands. A Russian commentary at the time remarked that in "maps published in...regions of the country even the whole territory of the Kuril Islands is marked as Japanese.
"Such kinds of territorial disputes had long been dubbed as 'cartographic aggression.'
"For example, if Japan does not want to settle an old dispute with China over the Diaoytai Islands, also known as the Senkaku Islands in Japanese, it may mark the territory as Japanese." 
In November of 2009 the Japanese government reiterated the accusation that "the Russian Federation is illegally occupying four northern islands." 
The Russian Foreign Ministry responded by labelling as "unacceptable" a document issued by Tokyo identifying the alleged "illegal occupation by Russia" of the Kuril Islands, stating:
"We consider it necessary to stress that the Southern Kuril Islands are an inseparable part of the Russian Federation territory on legal grounds based on the WW2 results in accordance with the legally binding agreements and treaties between the ally states, as well as the UN Charter that was ratified by Japan." 
Last month then-Japanese Foreign Minister Katsuya Okada spoke of the Kurils being "illegally occupied by Russia."
When similar statements were made by Okada's successor, Seiji Maehara, chairman of the international affairs committee in the Russian State Duma Konstantin Kosachev remarked:
"Such an inappropriate and tough statement by the Japanese foreign minister is regrettable.
"Like the parliament of that country did earlier, Tokyo is consistently
toughening its stance, pointing out the debatable status of the Kuril islands. That may only drive the situation into a deadlock." 
It is this intensified policy of Japanese recalcitrance and revisionism that Washington has now squarely endorsed. Although State Department spokesman Philip Crowley qualified his comments of November 1 by saying the Article 5 military component of the Treaty of Mutual Cooperation and Security between the United States and Japan would not be invoked as long as Japan did not administer the Kurils, the door was left open for the activation of the article should Japan succeed, peacefully or otherwise, in gaining possession of the islands and the transition be recognized by Washington.
But the Kuril, as well as the Senkaku/Diaoyu, Spratly and Paracel, islands are minor chess pieces in a far broader stratagem. The U.S. intends to accelerate its return to and domination over the Asia-Pacific region and China and Russia are the main obstacles to its doing so.