The Senate could prevent the President's nominee from serving as a federal judge, if they refuse to confirm the President's nominee.
Explanation:
Under Article II, of the United States Constitution; the President has the power to elect candidates for Supreme Court Judges, but it also states that the Senate shall advice and consent the President's decision.
Before the President can officially present his nominee, he has to follow certain steps that involve sessions in which the nominee should present and answer questions from the Senate's Judiciary Committee. The Committee acts as a Representative Committee for the whole Senate, and if they approve (three-fifths are required), they send their vote to the entire Senate, this confirmation allows the President to appoint the nominee for federal judge.
