David Courtney Coates was an American publisher and printer, labor union leader and socialist politician who served as the 11th Lieutenant Governor of Colorado, secretary and president of Colorado's State Federation of Labor, president of the American Labor Union and chairman of the National Party.

The National Party was an early-20th-century national political organization in the United States founded by pro-war defectors from the Socialist Party of America (SPA) in 1917. These adherents of the SPA Right first formed a non-partisan national society to propagandize the socialist idea called the Social Democratic League of America. Many of these individuals were eager for the formation of an alternative political organization to both the old parties and the anti-war SPA and eagerly latched on to a burgeoning movement for a new party that sprouted in 1917.