TOKYO – In the end, the weather just wasn’t bad enough. Japan’s Liberal Democratic Party (LDP), which has dominated politics since 1955, claimed victory in Sunday’s national election as it and its coalition partners took a comfortable majority in the Diet. Prime Minister Koizumi Junichiro’s celebrations have been muted, however: The LDP’s failure to win an outright majority in the lower house will embolden obstructionists within his own party who oppose his reform agenda.