In the first few minutes after the 1981 shooting by John Hinckley, Mr Reagan's top aides withdrew to the Situation Room which is located in the basement of the White House.
Audio tapes just released reveal the confusion among top presidential aides over the wherabouts of the triggers for the US nuclear arsenal as Ronald Reagan recovered from an assassination attempt.
In the first few minutes after the 1981 shooting by John Hinckley, Mr Reagan's top aides withdrew to the Situation Room which is located in the basement of the White House.
There, behind electronic locks and guarded by uniformed Secret Service agents, they tried to manage the fallout from the shooting.
Normally no tape recorders are allowed in the Situation Room, but National Security Adviser Richard Allen decided that on this occasion a recording was necessary to ensure an indisputable record of events
According to the tapes, the aides were primarily concerned about national security issues.
'Get the football'
First of all they discuss, with some confusion, the whereabouts of the "football", slang for the briefcase that travels with the president and contains the codes for launching nuclear missiles.
National Security Adviser Richard Allen: "We should get one [football] over here. We have a duplicate one here."
Secretary of State Alexander Haig: "Get the football over here."
Richard Allen: "There is one at the military aide's office. The football is in the closet."
Their concern about the "football" was only increased by news that the Soviet Union had sent a submarine on a closer approach to US interests than normal.
Under sedation
As the submarine moved closer than the Soviets had been before, it raised the question of whether to increase US defence alerts.
While Mr Reagan was under sedation the chain of command passed to Vice President George Bush.
But Mr Bush was on an aeroplane over Texas at the time of the incident and until he returned to Washington the question of who held ultimate authority remained confused.
In an exchange which reveals how little information the men had, Secretary of State Alexander Haig told Press Secretary David Gergen that he was taking control:
Gergen: "Is he [Reagan] under sedation now?"
Haig: "He's not on the operating table."
Gergen: "He is on the operating table!"
Haig: "So then the helm is right here. And that means right in this chair for now, constitutionally, until the vice president gets here."
In fact, constitutionally, Alexander Haig was wrong, three other Cabinet members were ahead of him in the hierarchy.