Gretchen Carlson, who is marking one year on "The Real Story" today, asked a former Secret Service agent whether someone should be fired over the fence-jumper breach.

Yesterday it was revealed that the intruder, Omar Gonzalez, made it much further into the White House than previously reported.  The president was not there during the Sept. 19 incident.

On Capitol Hill today, Secret Service director Julia Pierson was grilled by lawmakers who were outraged over how the breach could have happened.

Pierson admitted that the security system that was in place fell apart and faced accusations that the seriousness of the breach was intentionally downplayed.

Dan Emmett, a former Secret Service agent for more than 20 years and author, said it was "lucky" that an off-duty agent happened to intervene after Gonzalez penetrated five rings of security.

Emmett said the Secret Service "failed miserably" and the breach could have led to something much worse.

He called Pierson a friend and an "outstanding individual," but said she should either resign or retire.

"Any time you have catastrophic failure in an organization like this, one of the things you need to do in the beginning is simply relieve those in charge. In other words, invite them to retire or move on to another profession or into private life. ... You have to think what is best for the Secret Service, what is best for the president," said Emmett.

Watch his full interview above.