Secret Service started assigning an agent to the small group of reporters who travel with the president so they would know whether someone was infiltrating the group.
After Reagan's shooting, presidents also were driven into buildings through underground parking garages. When that's not possible, a cover is erected around the entrance to obstruct the line of sight as the president gets into or out of a vehicle.
“Nobody walks through the front door any more," said retired supervisory Secret Service agent Bobby McDonald, now a criminal justice lecturer at the University of New Haven. “Presidents and protectees of the Secret Service have seen more loading docks and have walked through more kitchens than ever before.”
Changes also followed the assassination of John F. Kennedy in 1963 as he drove through Dallas in a convertible, former agents say. Presidents no longer sit in open vehicles but wave to onlookers through the thick glass of a heavily armored limousine nicknamed “the beast.”
Mounting security concerns a month after the Oklahoma City bombing at a federal building prompted the closure. There were other changes, too, such as air traffic restrictions after a small plane crashed into the White House lawn in 1994. As well, gunfire twice hit the mansion that same year.
Then-President Bill Clinton said closing the street was necessary to protect against the kind of attack seen in Oklahoma City but vowed that “people's access to the White House and their president” would not be impeded. He even vowed that protesters would still have the right to walk up to the White House property. Many still do.