Is There a Consistent Ideology or Philosophy Underlying the Position?

If you're talking to a typical leftist or a liberal and you say I agree with you about abortion, you are basically in agreement. He supports the right to abortion because he thinks the government can't violate the right of woman to choose what to do with her body. But there's a fundamental disagreement if that person does not believe you have a right to an abortion. The issue is, is there some consistent ideology or philosophy underlying his particular position with which you disagree? If that's not the case, feel free to associate with him.