National Review Online, June 14, 2011.
Flag Day is unusual. Commemorating the birthday of the American flag, adopted in the midst of the American Revolution by the Second Continental Congress, Flag Day is not an official federal holiday. Instead, by an act of Congress passed in 1949, the president is merely “requested to issue each year a proclamation, calling on United States Government officials to display the flag of the United States on all Government buildings on Flag Day; and urging the people of the United States to observe Flag Day as the anniversary of the adoption on June 14, 1777.” President Obama has again honored that request, as have all his predecessors since President Truman.
American Enterprise Institute