This is how Secret Service protection has changed for presidents over the years

As the world has vastly changed, so has protection for presidents since the days when the public could come to the White House to meet Abraham Lincoln. Protective details have grown in size, responsibility and technology over more than a century of the Secret Service protecting presidents. When presidents leave the White House in modern times, they're accompanied by a phalanx of Secret Service officers and agents. Cars can no longer drive past what is often dubbed “the people’s house” at 1600 Pennsylvania Ave. The fence has been raised, and don’t even try to get past the gate without an appointment or badge.