 Complete the following phrase:  As distressing as these border conflicts were, the PolishSoviet War of 19191921 was the most important series of military actions of the era. Piłsudski had entertained far-reaching anti-Russian cooperative designs in Eastern Europe, and in 1919 the Polish forces pushed eastward into Lithuania, Belarus and Ukraine by taking advantage of the Russian preoccupation with a civil war, but they were soon confronted with the Soviet westward offensive of 19181919. Western Ukraine was already a theater of the PolishUkrainian War, which eliminated the proclaimed West Ukrainian Peoples Republic in July 1919. In the autumn of 1919, Piłsudski rejected urgent pleas from the former Entente powers to support Anton Denikins White movement in its advance on Moscow. The PolishSoviet War proper began with the Polish 