Democratic Senate candidate Heidi Heitkamp and her Republican opponent, Rep. Rick Berg, attend a North Dakota Chamber of Commerce forum in Bismarck last week. Dale Wetzel/AP hide caption

toggle caption Dale Wetzel/AP

President Obama and Mitt Romney campaign in August: Obama in Leesburg, Va.; Romney in Waukesha, Wis. AP hide caption

toggle caption AP

A collection of political direct-mail pamphlets produced by the Mammen Group. Lauren Rock/NPR hide caption

toggle caption Lauren Rock/NPR

NPR thanks our sponsors

Become an NPR sponsor