A nearly unbroken line of Liberal Democratic Party politicians has headed the government since the party's 1955 formation. This dominance, however, was shaken by the stunning victory of the Democratic Party of Japan in the July 2007 House of Councilors election. In this reshaped political landscape, the two Diet chambers are controlled by different camps.
Despite DPJ claims that it aims to wrest control from the LDP in the next Lower House election, the fact is that political power is a complex phenomenon with many moving parts. Speculation lingers that further realignments of the parties, which have undergone a series of regroupings in the past two decades, await.
Following is an overview of the parties currently represented in the Diet: