The US Supreme Court ruled on same-sex marriage before Trump and even Trump has not been able to revert the decision. Everyone was surprised when the US Supreme Court refused to consider the cases brought by Trump about the fraud in the election and he was sure the three justices he had appointed were going to stand by him. They did not because they are Justices in the US Supreme Court and they have to respect the US Constitution and precedence: when people are granted a right of any kind, it cannot be withdrawn. That's why cases against Obama Care all failed.