Ralph Nader appeared Thursday on Fox News to discuss a democratic primary he was organizing against President Barack Obama to "hold his feet to the fire."

"The important thing here is if he's not challenged from the progressive-liberal wing of his party, that elected him, it'll be a very dull campaign, people will not be very enthusiastic, more and more people will stay home, it's not good for him," Nader said. "If he's a good debater, if he knows his facts, he'll want to be challenged because he'll come out much sharper."

When asked about the possibility of a third party candidate succeeding in the 2012 presidential election, Nader said it would be a hurdle for anyone who wasn't a billionaire.

"It's a two party dictatorship unless you're worth billions of dollars."

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