At the congress of the Second International in Amsterdam in 1904, it became clear that the individual groupings had fundamentally different ideas regarding the participation of socialists in governments and the implementation of democratic reforms.
Congress of the Second International in Amsterdam, 14 August 1904, black-and-white photograph, photographer unknown; source: with kind permission © Archives of Social Democracy, Friedrich-Ebert-Stiftung Bonn, signature 6/FOTB015495, https://www.fes.de/archiv-der-sozialen-demokratie/.