Sen. Max Baucus, D-Mont. left, and Rep. Dave Camp, R-Mich., speak about overhauling tax policy to an audience at the 3M tech company on Monday. Hannah Foslien/AP hide caption

itoggle caption Hannah Foslien/AP

Democratic Rep. Elijah Cummings of Maryland is a ranking member of the House Committee on Oversight and Government Reform. He's released documents that suggest that the IRS targeted progressives as well as Tea Party groups. Alex Wong/Getty Images hide caption

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House Oversight and Government Reform Committee Chairman Darrell Issa (right) speaks with the committee's ranking Democrat, Elijah Cummings, during a hearing last month. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

The Club for Growth is backing a candidate running against Republican Rep. Mike Simpson (shown in this screen shot from the PrimaryMyCongressman.com site) in Idaho's 2014 GOP primary. PrimaryMyCongressman.com hide caption

itoggle caption PrimaryMyCongressman.com