ADVANCE FOR USE MONDAY, OCT. 22, 2012 AND THEREAFTER - FILE - In this Thursday, Aug. 23, 2012 file photo, supporters of Republican presidential candidate, former Massachusetts Gov. Mitt

 

              ADVANCE FOR USE MONDAY, OCT. 22, 2012 AND THEREAFTER - FILE - In this Thursday, Aug. 23, 2012 file photo, supporters of Republican presidential candidate, former Massachusetts Gov. Mitt
ADVANCE FOR USE MONDAY, OCT. 22, 2012 AND THEREAFTER - FILE - In this Thursday, Aug. 23, 2012 file photo, supporters of Republican presidential candidate, former Massachusetts Gov. Mitt Romney, sing the national anthem during a campaign event in Hobbs, N.M. In the sheer quantity of negative advertising and amount of dollars being spent, 2012 may mark the birth of an unprecedented era of negative campaigning, according to political scientists and campaign watchers. Contributing to the atmosphere is our extended campaign cycle of today, in which the barbs start flying long before the post-convention, fall campaign. (AP Photo/Evan Vucci)