As of 2015, only citizens and military personnel living or serving oversees are allowed to submit absentee ballets via fax or email. Citizens living within the United States at the time of an election are almost always required to be physically present when voting.
The Uniformed and Overseas Citizens Absentee Voting Act (UOCAVA) of 1986 is the U.S. law that dictates who may or may not cast an absentee ballet. The displaced victims of Hurricane Sandy in New Jersey were allowed to vote through fax or email during the 2012 election cycle due to special circumstances. Security and the integrity of the vote are the primary reasons the United States has yet to adopt long-distance electronic voting methods altogether.