 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 