With his approval ratings in free-fall, Japanese Prime Minister Yukio Hatoyama has resigned less than a year after winning a landslide election. The biggest blow to his office came after he broke a campaign promise to move the huge United States military base from Okinawa. With four Prime Ministers in four years, some are starting to wonder if Japan's leadership can ever come to grips with the country's many problems. Jeff Kingston of Temple University, Japan Campus, said it's little wonder that voters are disappointed. This is damaging both economically and diplomatically, said Phil Deans, also of Temple University, Japan Campus. "The frequent change in Japan's leadership is especially unsettling to the country's strategic and economic partners, particularly China," Deans said.