Four justices have to sign on in order to accept a case to be argued before the Supreme Court, while five justices are needed for a majority opinion. The court could wait for a state to pass a bill criminalizing abortion, allow that to snake through the lower court system and then make its way to the Supreme Court to be considered. Or, Cohen explained, it could take up one of dozens of pending cases related to abortion-restriction laws. By upholding a law that, say, banned abortion after 20 weeks or outlawed certain types of procedures, the court could effectively overturn Roe v. Wade.