Lest we forget the origins of Labor Day:
The first Labor Day in the United States was celebrated on September 5, 1882 in New York City. In the aftermath of the deaths of a number of workers at the hands of the US military and US Marshals during the 1894 Pullman Strike, President Grover Cleveland put reconciliation with Labor as a top political priority. Fearing further conflict, legislation making Labor Day a national holiday was rushed through Congress unanimously and signed into law a mere six days after the end of the strike. Cleveland was also concerned that aligning a US labor holiday with existing international May Day celebrations would stir up negative emotions linked to the Haymarket Affair. All 50 U.S. states have made Labor Day a state holiday.
read the rest on ye olde wikipedia.