December 4, 1906 – The National Federation of Postal Clerks was chartered on this date. (from the Daily Bleed)
December 4, 1951 - Walter Reuther, President of the United Auto Workers, was elected head of the Congress of Industrial Organizations (CIO). Four years later, he led the merger of the CIO and the American Federation of Labor to form the AFL-CIO. (From Workday Minnesota)
December 4, 1969--Chicago Black Panthers Fred Hampton and Mark Clark and 2 others were murdered by police, with assistance from the FBI.
December 4, 1970--Cesar Chavez was jailed for 20 days for refusing to call off the Salinas lettuce boycott. (from the Daily Bleed)