Flag etiquette: when to fly the flag at half-staff

Half Staff Displays  . . . "Flying the flag at half-staff is an area of flag etiquette that most people want to make sure they get right. It is also an area for which the road to error is routinely paved with good intentions. With that in mind, we offer this refresher course as the all-important intersection where knowledge meets benevolence." . . .

USA Today photo

When should the flag be flown at half-staff?  "An easy way to remember when to fly the United States flag at half-staff is to consider when the whole nation is in mourning. These periods of mourning are proclaimed either by the president of the United States, for national remembrance, or the governor of a state or territory, for local remembrance, in the event of a death of a member or former member of the federal, state or territorial government or judiciary. The heads of departments and agencies of the federal government may also order that the flag be flown at halfstaff on buildings, grounds and naval vessels under their jurisdiction." . . . 
"In the early days of our country, no regulations existed for flying the flag at half-staff and, as a result, there were many conflicting policies. But on March 1, 1954, President Dwight Eisenhower issued a proclamation on the proper times. 

"The flag should fly at half-staff for 30 days at all federal buildings, grounds, and naval vessels throughout the United States and its territories and possessions after the death of the president or a former president. It is to fly 10 days at half-staff after the death of the vice president, the chief justice or a retired chief justice of the United States Supreme Court, or the speaker of the House of Representatives. For an associate justice of the Supreme Court, a member of the Cabinet, a former vice president, the president pro tempore of the Senate, the majority leader of the Senate, the minority leader of the Senate, the majority leader of the House of Representatives, or the minority leader of the House of Representatives the flag is to be displayed at half-staff from the day of death until interment. " . . .  Full article here.