I think pro-lifers honestly believe pro-choicers are evil and will never compromise their values on this issue.
They don't need to compromise their values. They just need to stop trying to force their values on others.
That's the problem with the way we view government and its relationship to society. Because we've largely accepted the myth that government is the be-all, end-all expression of society, we assume that government should have something to say about everything. If it's good, government should encourage it, or even make it mandatory. If it's bad, government should regulate it, or ban it outright.
We've lost track of the conception of government as protector of freedom, and, instead, adopted the authoritarian view that government is there to tell us how to live in any and all cases.