Even if "You can't compromise on murder" is a platitude to you, it is a principle to me. And I don't think babies are still torn limb from limb because of it.
But I can't answer on whether or not we should compromise on strategy, because I'm not clear on what you mean. I don't see how supporting someone who wants abortion legal is strategically wise, but let us suppose it is. When you help put someone in office who will defend abortion, are you not defending abortion yourself, albeit indirectly?
Of course we must understand the reality of things as we fight to end abortion. That isn't something we can ignore. Still, I don't think we need to fight by the "rules of reality", which strike me as having the meaning "rules of the world". I have two reasons. One, I don't feel overly bound by "reality". There is much more than the reality we see around us, and with God all things are possible. Secondly, our Lord has commanded us to live in a way that defies all the world's rules and wisdom. Our fight isn't necessarily doomed if we conduct it in a way that defies the rules and wisdom of the world we live in.