FILE - In this Aug. 13, 2012 file photo, President Barack Obama laughs as he talks with people during a visit to the Iowa State Fair in Des Moines, Iowa. Call it the campaign trail scht

 

              FILE - In this Aug. 13, 2012 file photo, President Barack Obama laughs as he talks with people during a visit to the Iowa State Fair in Des Moines, Iowa. Call it the campaign trail scht
FILE - In this Aug. 13, 2012 file photo, President Barack Obama laughs as he talks with people during a visit to the Iowa State Fair in Des Moines, Iowa. Call it the campaign trail schtick. Have you heard the one about the kid who thinks President Barack Obama's job is to "approve this message?" Or the time Mitt Romney compared another presidential run to giving birth? The jokes at presidential fundraisers and rallies are easy applause lines for Obama and Romney, a way to keep supporters entertained before more weighty subjects like Medicare, taxes and foreign policy. A good sense of humor has served presidential candidates well in the past. So it's little wonder why both Obama and Romney are using the same technique. (AP Photo/Carolyn Kaster, File)