I think there is room for compromise on what is not, essentially, a moral issue. You can compromise on spending and taxes, but abortion is a question of killing the innocent. You shouldn't compromise on doing what is right - "right" having a moral, not practical, meaning.
Maybe a better way to say it is this: You shouldn't compromise on what God commands. God doesn't command, "You shall not have an income tax more than 30%." He does command, "You shall not murder." That's why I would compromise on taxes, and not on abortion.
Well said!