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. It means a very important person/ a tragedy has happened to our nation.