Note the lag time between event and response.
Terrorists Kill Thousands in An Attack On the World Trade Center and the Pentagon, September 11, 2001:
For Immediate Release
Office of the Press Secretary
September 12, 2001Honoring the Victims of the Incidents on Tuesday, September 11, 2001
By the President of the United States of America
A ProclamationAs a mark of respect for those killed by the heinous acts of violence perpetrated by faceless cowards upon the people and the freedom of the United States on Tuesday, September 11, 2001, I hereby order, by the authority vested in me as President of the United States of America by the Constitution and the laws of the United States of America, that the flag of the United States shall be flown at half-staff at the White House and upon all public buildings and grounds, at all military posts and naval stations, and on all naval vessels of the Federal Government in the District of Columbia and throughout the United States and its Territories and possessions until sunset, Sunday, September 16, 2001….
Supreme Court Chief Justice William Rehnquist Dies, September 3, 2005:
For Immediate Release
Office of the Press Secretary
September 4, 2005Proclamation by the President: Death of William HR Rehnquist
A Proclamation by the President of the United States of AmericaAs a mark of respect for William H. Rehnquist, Chief Justice of the United States, I hereby order, by the authority vested in me by the Constitution and laws of the United States of America, including section 7 of title 4, United States Code, that the flag of the United States shall be flown at half-staff at the White House and on all public buildings and grounds, at all military posts and naval stations, and on all naval vessels of the Federal Government in the District of Columbia and throughout the United States and its Territories and possessions until sunset, Tuesday, September 13, 2005….
Hurricane Katrina Kills Thousands and Causes Widespread Destruction on the Gulf Coast, August 26, 2005:
For Immediate Release
Office of the Press Secretary
September 4, 2005Honoring the Memory of the Victims of Hurricane Katrina Proclamation
A Proclamation by the President of the United States of AmericaAs a mark of respect for the victims of Hurricane Katrina, I hereby order, by the authority vested in me by the Constitution and laws of the United States of America, that the flag of the United States shall be flown at half-staff at the White House and on all public buildings and grounds, at all military posts and naval stations, and on all naval vessels of the Federal Government in the District of Columbia and throughout the United States and its Territories and possessions until sunset, Tuesday, September 20, 2005….