 In 1919 he commanded Operation Minsk.He disagreed with the Polish Commander-in-Chief, Józef Piłsudski, which cost him his post, and joined the National Democratic opposition to Piłsudski.From June to December 1923 he was Minister of Military Affairs; during that time he challenged Piłsudski to a duel for a perceived slight (Piłsudski refused the challenge).