Abortion in the United States is legal, subject to balancing tests tying state regulation of abortion to the three trimesters of pregnancy, via the landmark 1973 case of Roe v. Wade, the first abortion case to be taken to the Supreme Court. Every state has at least one abortion clinic. However, individual states can regulate and limit the use of abortion or create "trigger laws", which would make abortion illegal within the first and second trimesters if Roe were overturned by the Supreme Court of the United States. Nine states—, , , , , , , and —still have unenforced pre-Roe abortion bans in their laws, which could be enforced if Roe were overturned. In accordance with the US Supreme Court case of Planned Parenthood v. Casey (1992), states cannot place legal restrictions posing an undue