Cobelligerence

9 I wrote to you in my letter not to associate with sexually immoral people— 10 not at all meaning the sexually immoral of this world, or the greedy and swindlers, or idolaters, since then you would need to go out of the world. 11 But now I am writing to you not to associate with anyone who bears the name of brother if he is guilty of sexual immorality or greed, or is an idolater, reviler, drunkard, or swindler—not even to eat with such a one (1 Cor 5:9-11). 
14 Therefore, my beloved, flee from idolatry...21 You cannot drink the cup of the Lord and the cup of demons. You cannot partake of the table of the Lord and the table of demons.
25 Eat whatever is sold in the meat market without raising any question on the ground of conscience. 26 For “the earth is the Lord's, and the fullness thereof.” 27 If one of the unbelievers invites you to dinner and you are disposed to go, eat whatever is set before you without raising any question on the ground of conscience. 28 But if someone says to you, “This has been offered in sacrifice,” then do not eat it, for the sake of the one who informed you, and for the sake of conscience (1 Cor 10:14,21, 25-28).
14 Do not be unequally yoked with unbelievers. For what partnership has righteousness with lawlessness? Or what fellowship has light with darkness? 15 What accord has Christ with Belial? Or what portion does a believer share with an unbeliever? 16 What agreement has the temple of God with idols? For we are the temple of the living God (2 Cor 6:14-16).

One of the issues in the prolife movement is cobelligerence. Should evangelical prolifers combine forces with Catholic prolifers?

Abolish Human Abortion takes the position that cobelligerence is wrong because Catholics are idolaters. What about that?

i) I agree with AHA that Catholics are idolaters. I won't bother to defend that claim in this post, since that's not the point of my post.

ii) In addition, two parties can be mutual allies in one respect,  but mutual critics in another respect. Cobelligerence on abortion does not and should not preclude evangelicals from critiquing Catholicism. And it's not as if Catholics refrain from critiquing evangelicalism. 

iii) Mind you, there are better and worse ways of doing that. It needs to be an intelligent critique that's able to field stock Catholic replies to the contrary. 

In addition, it shouldn't be motivated merely by a desire to distance abolitionism from the prolife movement. Scripture condemns displays of spiritual ostentation which are designed to impress other people. 

iv) Ironically, AHA has it backwards. Paul doesn't forbid Christian association with idolaters. Indeed, Paul considers that unavoidable (1 Cor 5:9-10). Christian association with idolaters is permitted rather than prohibited.

v) Paul discusses degrees of licit or illicit association. 

a) Paul permits private meals between pagans and Christians (1 Cor 10:25-27), with a caveat (v28). 

b) Paul forbids Christian participation in pagan cultic ceremonies (1 Cor 10:14-22; 2 Cor 6:14-16). 

c) Paul forbids Christian cultic meals (the eucharist, agape feast) between believers and impenitent professing Christians (1 Cor 5:11). That calls for excommunication. 

vi) 2 Cor refers back to this discussion. It's referring to fellowship in the technical sense of the congregational life of the church, in contrast to pagan ceremonies. 

If we map this onto cobelligerance, Pauline strictures permit evangelicals to work with Catholics in opposing abortion, but forbid evangelical participation in the Mass (to take one example).