<P> Those who continued to resist the "military solution" including nationalists with unquestionable patriotism, such as generals Jotaro Watanabe and Tetsuzan Nagata and ex-Foreign Minister Kijūrō Shidehara were driven from office or an active role in the government . </P> <P> A turning point came with the ratification of the London Naval Treaty of 1930 . Prime Minister Osachi Hamaguchi and his Minseito party agreed to a treaty which would severely limit Japanese naval power . This treaty was strongly opposed by the military, who claimed that it would endanger national defense, and was portrayed by the opposition Rikken Seiyukai party as having been forced upon Japan by a hostile United States, which further inflamed growing anti-foreign sentiment . </P> <P> The Japanese system of party government finally met its demise with the May 15 Incident in 1932, when a group of junior naval officers and army cadets assassinated Prime Minister Inukai Tsuyoshi . Although the assassins were put on trial and sentenced to fifteen years' imprisonment, they were seen popularly as having acted out of patriotism and the atmosphere was set where the military was able to act with little restraint . </P> <P> Japan had been involved in the Asian continent continuously from the First Sino - Japanese War, Boxer Rebellion, Russo - Japanese War, World War I and the Siberian Intervention . During the term of Prime Minister Tanaka Giichi from 1927 to 1929, Japan sent troops three times to China to obstruct Chiang Kai - shek's unification campaign . In June 1928, adventurist officers of the Kwantung Army embarked on unauthorized initiatives to protect Japanese interests in Manchuria, including the assassination of a former ally, warlord Zhang Zuolin, in hopes of sparking a general conflict . </P>

When did the militarists take over the civilian government of japan