As Japan’s House of Representative election of 30 August looms, it is looking increasingly likely that the long-ruling Liberal Democratic Party (LDP) could be voted out of power for the first time.* In fact, it could be a debacle for the party, with the opposition Democratic Party of Japan (DPJ) and its pre-electoral allies winning a very large majority.
Yomiuri reports, from a recent poll, that the DPJ could win more than 300 seats. The chamber has 480 seats, so the majority could be very big. Three hundred of the seats in the house are elected in single-seat districts by plurality, and the rest by proportional representation; however, the latter are not compensatory, so a party or pre-electoral coalition that wins lots of the district races can be significantly over-represented. (Please see the planting prior to the September, 2005, election for details on this MMM system.)
More from Yomiuri:
Of the 271 candidates the DPJ is fielding in the single-seat constituency race, nearly 200, or about 70 percent, look set to win, while about 40 are considered too close to call.
As for the LDP, it has relatively few safe seats (amazing!), and some of those where it is expected to do well are those in which it is facing the DPJ’s less popular pre-electoral allies (the Social Democratic Party or the NewNew Party Japan, rather than a candidate of the DPJ itself).
As for [LDP ally] New Komeito, eight of its members are running for reelection in the single-seat constituencies, but the party is unlikely to see the entire group returned to office. The party is having a difficult time winning support, especially in Tokyo and Osaka constituencies.
The DPJ could win around 80 of the list-tier seats. That would be 44%. Yet even with a likely ~40% party-list vote, all those mostly two-candidate races in the nominal tier of the MMM system would translate into a huge swing overall.
Interest in the election is high, and the 20% of poll respondents who say they are still undecided is actually a good deal lower than in past elections. (See the Yomiuri link above for details.)
A student shared a link to a site with nice maps. The text there is all in Japanese, but scroll down. All that red on the map indicates single-seat districts likely to be won by the DPJ, while blue is the LDP.
* The LDP lost control of the House of Councilors, the by-no-means weak second chamber, in July 2007. However, the cabinet depends on the exclusive confidence of the first chamber, and the LDP has never been defeated at a general election for this body. It was out of power briefly in the early 1990s when, due to splits (largely over the issue of reform of the electoral system), it failed to win a majority of seats.