 Complete the following phrase:  After the German Ober Ost garrisons were withdrawn from the Eastern Front following the Armistice, both Soviet Russian armies and Polish ones moved in to fill the vacuum. The newly independent Polish state and the Soviet government each sought territorial expansion in the region. Polish and Russian troops first clashed in February 1919, with the conflict developing into the PolishSoviet War. Unlike the Soviets previous conflicts, this had greater implications for the export of revolution and the future of Europe. Polish forces pushed into Ukraine and by May 1920 