But the law passed by Congress setting Election Day only allows a state to pick its electors on a later date if it has already held an election on Election Day and `` failed to make a choice '' on that day . Presidential Election Day is set by Congress under its authority in the Constitution . Election dates can only be changed if a new federal law is passed . But a state will probably be allowed to postpone voting only in disaster - affected areas . Statewide postponement of the presidential vote is an open legal question .
Presidential Election Day is set by Congress under its authority in the Constitution . Election dates can only be changed if a new federal law is passed . But a state will probably be allowed to postpone voting only in disaster - affected areas . Statewide postponement of the presidential vote is an open legal question .