"There was a time when a US president could travel from his inauguration in an open-top car."
John F Kennedy was the last president to do that.
He was also the last president to be sworn into office without the protection of a bullet proof screen.
Those days have long gone.
Secret Service agents now swarm a new president's blast-proof limousine as it travels along Pennsylvania Avenue.
But the inauguration still presents a security nightmare.
And Barack Obama's inauguration on Tuesday will provide the biggest challenge yet.
"Secret Service agents will mingle with the crowds"
Inauguration Day 2009 may well be the biggest show on earth.
What if Mr Obama was assassinated on that fateful day ?