As it had during the Depression in the 1930s and boom of the 1940s, the economy's macroeconomic performance remained crucial to African American status during the half century following World War II. During the quarter century beginning in 1948 and ending with the sharp recession of 1974–75, average family income doubled in the United States. Backed by the teaching of eminent sociologists, the typical American believed government action such as legislation, judicial decisions, and executive decrees had little affect on the deeply held social mores and practices driving race relations. But civil rights activists understood that by sanctioning discrimination and segregation government was the most powerful supporter of prevailing mores and practices. In the mind of the average citizen wishing to abide by the law, what moral dilemma existed between American political ideals and racist practices when the highest courts in the land had declared segregation legal, when U.S. armed forces deemed blacks unfit to serve in the same units as whites, and governments at all levels discriminated against blacks in as blatant fashion as the most unrepentant racial bigot? Civil rights leaders gambled that people's beliefs and practices toward blacks would adjust to the ideas sanctioned by governments following principles of justice and fairness.