(CNN) – On Tuesday night presidential candidates will lock horns in a debate in Chicago. The participants are not Republican or Democrat. They're third party candidates.

At tonight's debate: Jill Stein (Green Party), Gary Johnson (Libertarian Party), Virgil Goode (Constitution Party) and Rocky Anderson (Justice Party), all of whom have received little attention during this election. They're working to change that by pushing a message that focuses on issues that they believe are being ignored by Democrats and Republicans.