The reasons for a second conference included the opposition that the International Socialist Bureau was putting up against the Zimmerwald movement, the opposition of the bourgeois nationalists and the "gradually maturing plans for peace".
Alasan-asalan untuk konferensi kedua tersebut meliputi penentangan terhadap Biro Sosialis Internasional yang menentang gerakan Zimmerwald, menentang nasionalis-nasionalis burjois dan "secara bertahap mendewasakan rencana-rencana untuk perdamaian".