Biggest issue is most third parties tend to put up candidates that are either: complete cranks or well-meaning candidates that focus on issues with limited sali

Biggest issue is most third parties tend to put up candidates that are either: complete cranks or well-meaning candidates that focus on issues with limited salience with voters. That, and the framers of the US government basically wanted the US to operate with 2 parties because democracy was still considered fairly experimental at that time.