Mitt Romney speaks Dec. 16 at Missouri Valley Steel in Sioux City, Iowa. Chris Carlson/Associated Press hide caption

itoggle caption Chris Carlson/Associated Press

Rep. Michele Bachmann waves to supporters Friday in Sioux City before starting a 99-county bus tour of Iowa. Jeff Haynes/Reuters /Landov hide caption

itoggle caption Jeff Haynes/Reuters /Landov

President Obama speaks with small-business owners at Rausch's Cafe in Guttenberg, Iowa, during a three-day Midwest bus tour in August. Jim Watson/AFP/Getty Images hide caption

itoggle caption Jim Watson/AFP/Getty Images

President Obama addresses the media Thursday, with an electronic clock counting down to the end of the year. The payroll tax cut is due to expire then, unless Congress votes to extend it. Win McNamee/Getty Images hide caption

itoggle caption Win McNamee/Getty Images

President Obama delivers an economic speech Tuesday in Osawatomie, Kan., where Teddy Roosevelt issued a famous call for a "New Nationalism" 101 years ago. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP

T-shirts on display at the 2011 Republican Leadership Conference in New Orleans in June. With the holidays approaching, campaigns and retailers are hawking plenty of political merchandise. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images