Shortly after that, the pro-Iskra delegates split into two factions. Lenin and his supporters, the Bolsheviks, argued for a smaller but highly organized party, while Martov and his supporters, the Mensheviks, argued for a more massive and less disciplined party. In a surprise development, Trotsky and most of the Iskra editors supported Martov and the Mensheviks, while Plekhanov supported Lenin and the Bolsheviks. During 1903 and 1904, many members changed sides in the factions. Plekhanov soon parted ways with the Bolsheviks. Trotsky left the Mensheviks in September 1904 over their insistence on an alliance with Russian liberals and their opposition to a reconciliation with Lenin and the Bolsheviks.