A Secret Service agent stands guard at the Democratic National Convention in Charlotte, N.C., Tuesday, Sept. 4, 2012. (AP Photo/Jae C. Hong)

 

              A Secret Service agent stands guard at the Democratic National Convention in Charlotte, N.C., Tuesday, Sept. 4, 2012. (AP Photo/Jae C. Hong)
A Secret Service agent stands guard at the Democratic National Convention in Charlotte, N.C., Tuesday, Sept. 4, 2012. (AP Photo/Jae C. Hong)