Japan Foreign Minister Seiji Maehara resigned Sunday over an illegal donation scandal, dealing the latest blow to Prime Minister Naoto Kan's faltering government and threatening to diminish Japan's credibility in international circles. Mr. Maehara, considered by many to be a successor to Mr. Kan, was one of Japan's shortest-lived foreign ministers, with a tenure that barely spanned six months. Japan's political merry-go-roundthe past four prime ministers of the country lasted only about a year or lesshas raised painful questions as to whether Japanese politicians can tackle serious foreign policy issues, such as relations with China, and issues facing their economy such as public debt worth around twice the nation's annual economic output. Mr. Maehara, an influential member of the ruling Democratic Party of Japan and considered a possible successor to Mr. Kan, came under fire Friday after telling parliament that he has accepted donations from a foreign national in violation of Japan's political funding law. Mr. Kan appeared to throw his weight behind Mr. Maehara, saying in Japanese media reports, "He says he wants to examine the whole thing and then clearly explain it. I think that's good."