It may not have as much pull as you'd like it to, but considering other political movements of recent it has gotten a lot further (Occupy Wall Street as an example) and has actually put members in Congress and had an affect on our political system. I wouldn't go as far to say it's a full on third party as you're right, the Republican's have taken them under their wing per say, but they are an identity that people can specifically align themselves to with saying Democrat or Republican.
