In years since World War 1, the day has become a celebration of honor for those who died in all Americas wars, as well as those who are Veterans and current members of the US military. In 1971, Memorial Day was declared a national holiday. The United States celebrates this holiday the last Monday of May. Memorial Day Meaning  Reagans Speech. President Ronald Reagan is credited with reviving the practice of honoring Memorial Day and its meaning. One of his famous speeches was given at Arlington National Cemetery on Memorial Day in 1986.