Presidents, former presidents and presidents-elect are entitled to state funerals. It is left to the family to decide whether one should be held and how involved it should be.
The military, for instance, has a 138-page planning document that dictates everything from seating charts to floral arrangements. Processions must move at 20 mph. The footsteps of military guards are elaborately prescribed.
The State Department's protocol office draws up seating arrangements for foreign guests at religious ceremonies.
Since the Reagan family requested the full funeral protocol, President Bush put into motion a detailed chain of command, with most arrangements delegated to Washington-area Army officials. Military planners flew to California to consult with the family.
The former president died Saturday at his home in California. This morning, his body will be taken from a Santa Monica funeral home to his presidential library in Simi Valley, northwest of Los Angeles. After a private service for his family, his body will lie in the library's lobby, which will be open to the public for 30 consecutive hours.
On Wednesday, his body will be flown to Washington to lie in state in the Capitol Rotunda.
A service at the Washington National Cathedral, including a tribute by Bush, will be held Friday before the body is returned to the Reagan library in California for a sunset interment.
President John F. Kennedy's funeral in 1963 was modeled after Abraham Lincoln's, as requested by Jacqueline Kennedy in her first public statement after her husband's assassination.
Historians pored over musty documents in the middle of the night by flashlight - the Library of Congress' automatic lights could not be rigged to come on after hours - as the stunned country waited for a plan.
Reagan's family also may be looking to history:
John Adams did not lie in state in the White House, even though he died while his son, John Quincy Adams, was president. The elder Adams, the country's second president, and Thomas Jefferson, the third, died on the same day - July 4, 1826 - which perhaps complicated Adams' chances for a White House viewing.