FILE - In this April 16, 2008 file photo, Democratic presidential hopefuls, Sen. Hillary Rodham Clinton, D-N.Y., and Sen. Barack Obama, D-Ill., return from a commercial break during th

 

              FILE -  In this April 16, 2008 file photo, Democratic presidential hopefuls, Sen. Hillary Rodham Clinton, D-N.Y., and Sen. Barack Obama, D-Ill., return from a commercial break during th
FILE - In this April 16, 2008 file photo, Democratic presidential hopefuls, Sen. Hillary Rodham Clinton, D-N.Y., and Sen. Barack Obama, D-Ill., return from a commercial break during their debate at the National Constitution Center, in Philadelphia. In presidential politics, everybody's searching for "the moment." The campaigns don't know when or how it will come, but they watch for something _ awkward words or an embarrassing image _ that can break through and become the defining symbol of the other guy's flaws. Now all eyes are on the series of three presidential debates that starts Wednesday. (AP Photo/Charles Dharapak, File)