Former IRS official Lois Lerner, during March 5 testimony before the House Oversight and Government Reform Committee. Lerner has repeatedly invoked the Fifth Amendment during congressional appearances on the scandal. Lauren Victoria Burke/AP hide caption

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Sen. Mike Lee, R-Utah, speaks during the Iowa Faith and Freedom Coalition's Friends of the Family Banquet in Des Moines, Iowa, in November 2013. Lee is one of the few candidates calling for 17th Amendment repeal who have won office. Justin Hayworth/AP hide caption

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Sen. John McCain, an Arizona Republican, at the annual meeting of the World Economic Forum in Davos earlier this week. His state's GOP leadership has censured him for his "disastrous" record. Ruben Sprich/Reuters/Landov hide caption

itoggle caption Ruben Sprich/Reuters/Landov

The John Weld Peck Federal Building in Cincinnati, where many of the missteps by IRS workers who targeted conservative groups occurred. Al Behrman/AP hide caption

itoggle caption Al Behrman/AP

Guests stand after a Rand Paul speech at the Conservative Political Action Conference (CPAC) in Rosemont, Ill. Conservatives celebrated Tuesday's victory in Wisconsin's recall election. Scott Olson/Getty Images hide caption

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