By examining party-switching decisions among members of Japan's Liberal Democratic Party (LDP), this article shows how distributive policy programs exclusively available to the governing party attract incumbents to the party in power. In a stable electoral environment where the government party is likely to stay in power, legislators elected from infrastructure-poor constituencies are effectively tied to the party. However, when the party's electoral prospects are uncertain, legislators behave more sincerely and switch parties to match their policy preferences. It is also found that defectors elected from infrastructure-poor constituencies tended to return to the LDP once the party installed a stable surplus coalition.
