A bit late… but I found an interesting article in the Huffington Post on Labor Day history which gives some hints about global politics.
“The first Labor Day celebration in the United States can be traced to New York City’s Union Square on Sept. 5, 1882. It was designed as a way to appease city workers after numerous strikes and in some cases even violence.”
“Labor Day in many countries is celebrated as May Day or International Workers Day (May 1), which was originally spawned by Europe’s proletariat movement, largely inspired by Communism. In 1958, President Eisenhower designated May 1 as both Law Day and Loyalty Day. Each of these were specifically aimed at replacing the communist holiday with a religious or patriotic one.” (source)