Concession speeches are a tradition in U.S. politics that date back to the beginning of broadcasting, but they have no basis in the Constitution or election laws and nothing to do with determining the outcome of a contest.
The Constitution leaves the administration of elections to the states. While there are certain federal laws in place for federal elections, the results of an election to federal office in a given state are left for that state's officials to determine and for its state courts and lawmakers to regulate in the event of any dispute.
A speech serves to acknowledge the legitimacy of the democratic process and a peaceful transfer of roles. "So what the concession speech accomplishes is not really about whether the loser accepts his or her loss," Time writes. "It’s about the loser’s supporters being encouraged to do so."