In the first decades of the 20th century, it drew significant support from many different groups, including trade unionists, progressive social reformers, populist farmers and immigrants. However, it refused to form coalitions with other parties, or even to allow its members to vote for other parties. Eugene V. Debs twice won over 900,000 votes in presidential elections (1912 and 1920) while the party also elected two Representatives (Victor L. Berger and Meyer London), dozens of state legislators, more than a hundred mayors, and countless lesser officials. The party's staunch opposition to American involvement in World War I, although welcomed by many, also led to prominent defections, official repression, and vigilante persecution. The organization was further shattered by a factional war over how to respond to the October Revolution in the Russian Republic in 1917 and the establishment of the Communist International in 1919—many members left the party in favor of the Communist Party USA.