While the Russian invasion of Ukraine has been overwhelmingly condemned by the churches of the world, the support of the Russian Orthodox Church for the war poses difficult questions to the ecumenical community: in particular, whether that church’s support for the war and the extreme nationalist policies of President Putin constitute grounds for suspending it from the World Council of Churches (WCC) and other ecumenical bodies. The current ecumenical emphasis upon ‘dialogue’ acts as a deterrent to such action, but the WCC describes itself as a fellowship of churches that confess Christ as God and Saviour and therefore supreme over all other authorities. There are parallels with previous challenges in ecumenical history, most particularly 1930s Germany and the stand of the Confessing Church. While dialogue has its own importance the prime ecumenical commitment in conflict situations is to confess Christ, whatever the risks of division that this incurs.