The WSJ has this report.
"Japan's campaign finance laws have claimed yet another talented politician. Foreign Minister Seiji Maehara resigned on Sunday after admitting that he had received a small donation from a constituent who was not a Japanese citizen. Mr. Maehara's career may not be over, but this minor scandal comes when Prime Minister Naoto Kan is teetering, and the foreign minister was a strong candidate to succeed him. The crusade for moral purity in politics is crippling Japan's leadership."