The Democratic Party of Japan (DPJ) came to power in 2009 promising significant transportation sector reform, but it has struggled to implement its proposals. I argue that the DPJ's initiatives faltered due to the legacy of “efficiency clientelism.” Historically, Japanese transportation policy combined two imperatives: (1) encourage efficiency by raising the cost of energy-inefficient transportation, and (2) redistribute benefits to supporters of the incumbent Liberal Democratic Party (LDP). Because of the legacy of efficiency clientelism, DPJ campaign pledges—designed to appeal broadly to the general public by reducing transportation costs—ran up against the prospect of sharp declines in revenues and energy efficiency. Efficiency clientelism was well suited to political realities in Japan prior to the 1990s, but recent developments have undercut its viability. This raises profound questions about the sustainability of Japan's energy efficiency achievements.

The dominance of Japan's Liberal Democratic Party (LDP) was long buttressed by the existence of a strong political support base in the rural areas led by local politicians who worked on behalf of national LDP politicians seeking reelection. In recent years, municipal mergers have drastically weakened the LDP's support base by reducing the number of local politicians and redrawing electoral district boundaries. Surprisingly, the main opposition party, the Democratic Party of Japan (DPJ), could not take full advantage of these new institutional arrangements. Instead, local politicians have become more independent of both major parties. As a result, at a time of increasing numbers of floating voters, neither of Japan's two major parties has a reliable local base across the country. To succeed, both parties must pay attention to the changing needs of the increasingly independent—and very often still rural—localities.