The Social Democratic Party is a small party, but when it threatened to drop out of the ruling coalition if the government approved a plan for US bases in Okinawa, Prime Minister Yukio Hatoyama had to pay attention. If the SDP dropped out, the coalition would lose its majority in the upper house. So the US, used to getting its way with Japan on foreign policy matters, has to learn to be patient:
Daniel Sneider, a Japan expert at Stanford University, said the United States has yet to really take into account the significance of the political changes wrought by the August election. "Domestic politics matter in Japan now in a way that they didn't when you had a virtual one-party state for 50 years," he said. "Do elections and domestic politics influence foreign policy in the United States? Of course. Now they do in Japan, too."
Here's the full article from the Washington Post.