What do the Christian Institute, the Islamic Human Rights Commission, The Gay Times and comedian Rowan Atkinson all have in common? Ordinarily, you might think, very little, but all have recently spoken out against the Government’s plans to introduce an incitement to religious hatred law. Like other recent campaigns to ‘Make Poverty History’, to ‘Keep Sunday Special’, or to march against the war in Iraq, how would we react if such diverse groups decided to organise themselves and pool together their protest for a common cause?
‘Co-belligerence’ is a political or military term usually meaning an alliance between parties against a common foe....

...Within evangelicalism, the use of the term ‘co-belligerence’ was popularised by Francis Schaeffer who emphasised the importance of falling neither into separatism nor into compromising alliance: ‘A co-belligerent is a person with whom I do not agree on all sorts of vital issues, but who, for whatever reasons of their own, is on the same side in a fight for some specific issue of public justice.’...

...From the perspective of the cultural mandate, there are those who are not Christians but who by their inconsistency (because of God’s common grace) may agree with a Christian stance on a certain cultural issue. When this happens there may be the opportunity for co-belligerence...

....We must also be loving, loving our enemies and loving our co-belligerents who in other contexts may well be enemies of the gospel....

...Christians must realise that there is a difference between being a co-belligerent and being an ally. At times we will seem to be saying exactly the same things as those without a Christian base are saying...We must say what the Bible says when it causes us to seem to be saying what others are saying... But we must never forget that this is only a passing co-belligerency and not an alliance....

...While co-belligerence may be a necessary activity in our current context, it is also an activity requiring constant care, attention and mature theological reflection from those involved. We must be humble to realise that we cannot rely on our own strength in such situations but must pray for God-given wisdom and discernment if and when we decide to engage in co-belligerence.

http://www.jubilee-centre.org/pdfs/14-3%20Co-belligerence.pdf