Realizing that it could capitalize on its victory over GM, the UAW set out to boost its membership in the aftermath of the sit-down strike. The union increased staff, lowered initiation fees, and stepped up recruitment efforts, all with remarkable results. With only 88,000 dues-paying members at the settlement of the Flint strike in February 1937, the organization grew to close to 400,000 members by October of that year, making it one of the largest labor organizations in the country. While historians often credit the Wagner Act for increasing UAW membership, the Flint sit-down strike clearly played a critical role as well.
The UAW appealed to new members in part because of the concessions the strikers had managed to obtain from GM, including pay raises, a move toward hourly rates, the reinstatement of fired workers, and the settlement of grievances. As one Fisher One employee noted, worker morale had greatly improved as a result of the strike: "The inhuman high speed is no more. We now have a voice, and have slowed up the speed of the line. And [we] are now treated as human beings, and not part of the machinery. . . . It clearly proves that united we stand, divided or alone we fall" (Fine 328).
The UAW extended its hold over GM by launching a similar strike at the Chrysler Corporation, the nation's second largest automobile producer, in March 1937. Here, too, the UAW won formal recognition. By December 1941, just as the United States entered World War II, the UAW claimed a membership of 649,000; six months later, the union secured victory at the Ford Motor Company, the final bastion of anti-union sentiment within the automobile industry.
The Flint strike boosted union membership not only in automobile manufacturing, but in other mass-production industries as well. On the day following the GM-UAW settlement, for example, the United States Steel Corporation, which had long fought the establishment of independent unions within its factories, accepted the CIO's Steel Workers' Organizing Committee as the sole bargaining agent for employees at the world's second largest manufacturing company. In the face of such union victories, even UAW rival AFL, which had previously spurned calls for unions of skilled and unskilled workers within a single industry, began to transform some of its affiliated locals into industrial unions. Overall union membership skyrocketed to nearly 35 percent of the non-agricultural labor force by 1945, and it continued a slow but steady rise over the next two decades.
The Flint strike also dramatically increased the popularity of the sit-down strike as a bargaining tool among union organizers and disgruntled workers. Only 48 of the 2,712 strikes in 1936 were sit-down strikes, compared to 477 of 4,740 strikes the following year. About half of the sit-down strikes in 1937 were undertaken by workers seeking to gain union recognition from resistant employers. By mid-March of that year, public support for the tactic had sharply eroded as an increasing number of Congressional representatives began denouncing it. By the time the U.S. Supreme Court declared the sit-down strike an illegal seizure of property in 1939, its use had greatly declined within the labor movement.
Other protest groups pushing for social, economic, or political transformation, however, quickly adopted the basic tactic. Inspired by the Flint and other sit-down strikes, the Congress of Racial Equality, a newly established civil rights organization, began in the 1940s to conduct "sit-ins" to protest racial discrimination in public places. The first nationally publicized sit-in took place on February 1, 1960, when black college students refused to leave a whites-only Woolworth's lunch counter in Greensboro, North Carolina. Civil rights activists throughout the South quickly embraced the practice, forcing the desegregation of restaurants, theaters, pools, and other public facilities. Later that same decade, student demonstrators occupied buildings on college campuses across the United States to protest university decisions and to oppose the Vietnam War. Whether known as the "sit-down" or the "sit-in," the tactic of physically occupying strategic sites and refusing to budge has proven a potent weapon for change.