Here is a clear definition of what the church teaches... so there's no misunderstanding. Perhaps you may want to direct this to a pro-abortion politician.
To make such intrinsically evil actions legal is itself wrong. This is the point most recently highlighted in official Catholic teaching. The legal system as such can be said to cooperate in evil when it fails to protect the lives of those who have no protection except the law. In the United States of America, abortion on demand has been made a constitutional right by a decision of the Supreme Court. Failing to protect the lives of innocent and defenseless members of the human race is to sin against justice. Those who formulate law therefore have an obligation in conscience to work toward correcting morally defective laws, lest they be guilty of cooperating in evil and in sinning against the common good.