Many political scientists contend that third parties have consistently failed because

they never reflect the political mood of the nation.
serve as a safety valve for dissident political groups, preventing major confrontations and political unrest.
can only come into existence if they are organized around a single charismatic leader.
can only come into existence if they split off from one of the major political parties.
are incapable of being formed from scratch by individuals who are committed to a particular issue or ideology.