Minnesota Rep. Michele Bachmann signs autographs at the Pizza Ranch in Indianola, Iowa, on Wednesday. The restaurant was largely empty aside from a few local Iowans, media and Bachmann staff. Becky Lettenberger//NPR hide caption

itoggle caption Becky Lettenberger//NPR

Texas Gov. Rick Perry attends the Westside Conservative Club breakfast Wednesday in Urbandale, Iowa. Eric Gay/Associated Press hide caption

itoggle caption Eric Gay/Associated Press

Republican presidential candidate Rick Perry walks with former Marine officer Dan Moran during a campaign stop Wednesday in Council Bluffs, Iowa. Eric Gay/AP hide caption

itoggle caption Eric Gay/AP

Texas Gov. Rick Perry speaks at the Republican Jewish Coalition 2012 Presidential Candidates Forum in Washington, D.C., last week. Alex Wong/Getty Images hide caption

itoggle caption Alex Wong/Getty Images

Republican presidential candidate Texas Gov. Rick Perry talks with voter Jane High before speaking at the Scott County Republican party's Ronald Reagan Dinner on Nov. 14 in Bettendorf, Iowa. Charlie Neibergall/AP hide caption

itoggle caption Charlie Neibergall/AP

In this image taken from video and provided by Worldwide Pants, Inc., Republican presidential candidate Rick Perry presents the "Top Ten Rick Perry Excuses," on the set of the Late Show with David Letterman. AP hide caption

itoggle caption AP

Texas Gov. Rick Perry stumbled during Wednesday night's Republican presidential candidate in Auburn Hills, Mich., at one point seeking help from Rep. Ron Paul, (R-TX). Paul Sancya/AP hide caption

itoggle caption Paul Sancya/AP

GOP presidential candidates (from left) former Pennsylvania Sen. Rick Santorum, Rep. Michele Bachmann, former House Speaker Newt Gingrich, former Massachusetts Gov. Mitt Romney, businessman Herman Cain, Texas Gov. Rick Perry, Rep. Ron Paul, and former Utah Gov. Jon Huntsman, pose before a GOP presidential debate at Oakland University in Auburn Hills, Mich., on Wednesday. Paul Sancya/AP hide caption

itoggle caption Paul Sancya/AP