A Voters Guide – 10 Facts about campaign finance
9. Debates
It is important to recognize that debates are private events put on by private institutions, corporate entities, or private associations. Organizations like The League of Women Voters, or CNN often partner with local universities to host larger state or federal debates. Being that each event is private, the people holding the event are able to invite whomever they’d like. There is no law requiring a candidate for any office has to be invited to debate.
Those who follow politics closely are aware of this. Third party candidates for President, like Gary Johnson of the Libertarian Party in 2012, are usually not included in debates. For grass root or third party candidates, campaign finance restrictions are a crippling obstacle. If they are unable to raise the money to get their message out there is no other way for them to reach voters.