PayPal co-founder Peter Thiel, who has donated more than $2.5 million to a superPAC backing GOP presidential candidate Ron Paul, speaks at the National Press Club in Washington, D.C., in October. Chip Somodevilla/Getty Images hide caption

itoggle caption Chip Somodevilla/Getty Images

Texas Rep. Ron Paul (right) talks with the his presidential campaign manager, Jesse Benton, backstage at the Republican Party's Iowa straw poll last August. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

Fans of GOP presidential candidate Ron Paul show their support outside the Mesa Arts Center before Wednesday night's Republican debate in Mesa, Ariz. Ethan Miller/Getty Images hide caption

itoggle caption Ethan Miller/Getty Images

Rep. Ron Paul, R-Texas, during Thursday night's Republican presidential debate in Jacksonville, Fla. Paul J. Richards/AFP/Getty Images hide caption

itoggle caption Paul J. Richards/AFP/Getty Images

U.S. Rep. Ron Paul, shown at a campaign stop in South Carolina, spoke with NPR's All Things Considered today about the upcoming primaries, the possibility of a third-party run, taxes and other issues. John W. Adkisson/Getty Images hide caption

itoggle caption John W. Adkisson/Getty Images

Ron Paul greets supporters in Meredith, N.H., on Sunday, two days before he placed second in the state's Republican primary. Stephan Savoia/Associated Press hide caption

itoggle caption Stephan Savoia/Associated Press