The Siberian intervention, 1918-1922, served as a testing ground for Japan in search for a new kind of imperialism which attuned to the democratic ideals of the postwar world order. Pressured by Wilsonianism from without and 'Taisho democracy' from within, Japanese leaders tried alternatives, notably non-territorial penetration, to the traditional imperial path set forth by the Meiji foundationists. Domestically, Prime Minister Hara Takashi established, for the first time in modern Japanese history, cabinet supremacy over both the genr6 oligarchy and the military authorities in structuring and implementing foreign policy. With the backing of Army Minister Tanaka Giichi, Hara adopted a policy of 'cooperative expansionism', which sought a friendly relation with the Western powers in Siberia while expandi~g its sphere of influence on the continent. However, despite its professed moral intentions along with the Allies, once in Siberia, Japan looked starkly imperial. This alarmed the Western powers, especially the United States, as the US-Japanese friction over the reconstruction and management rights of the Siberian Railroad exposed so well. Moreover, even as Japan joined the Allies to support an anti-Bolshevik puppet, Kolchak, it unilaterally continued to also aid its own favourite puppet, Semenov, in building a Japanese-controlled buffer state in eastern Siberia. ln the spring of 1920, Hara's foreign policy in Siberia proved ineffective, as the United States and the other Western powers retreated their forces from Siberia. Now the Allied intervention was turned into an independent Japanese occupation, leaving the Hara cabinet in the storm of international criticism as well as hostile domestic public opinion. And just when Japan seemed to be cornered toward withdrawal, further complications such as Korean nationalism and the establishment of Lenin 's puppet state, the Far Eastern Republic, continued to postpone the final government decision to leave. When Japan finally withdrew from Siberia. empty-handed, m October 1922, the international community felt relieved to see that Japan 's imperial challenge to the new world order had been defeated. But at the same time, Japan 's failure to commit to internationalism as a new great power was a disappointment not only for the world but also for the Japanese liberals, with considerable impact on Japanese sentiment in the interwar years.