[4][page needed] Collective bargaining rights for most hourly workers in the United States were first given legal protection in 1933 by Section 7a of the National Industrial Recovery Act (NIRA).

Although NIRA did not specifically exempt agricultural laborers from the protection of the Act, the Roosevelt administration, eager to win the political support of farm-state members of Congress, argued that farm workers were excluded.

[5][page needed] When the National Labor Relations Act (NLRA) was enacted in 1935, it specifically exempted agricultural workers due to pressure from the "farm bloc" in Congress.

Six thousand drivers and packing workers in the Salinas Valley in California, represented by the Teamsters, struck on July 17, 1970 effectively preventing most of the nation's summer lettuce crop from reaching consumers.

[13] The strike ended on July 23, but the contract included a special agreement by the growers to give the Teamsters, not the UFW, access to farms and the right to organize workers into unions.

[19] An agreement to return jurisdiction over the field workers to the farm union was reached on August 12,[14][20] and FreshPict Foods (then owned by the Purex Corporation) and Inter-Harvest (part of the United Fruit Company) broke ranks with the other lettuce growers and signed contracts with the UFW.

[24] In late September 1970, the UFW asked consumers to join in a nationwide boycott of all lettuce which had not been picked by members of the United Farm Workers.

Kennedy and Johnson were attacked by an anti-union mob on the steps of the jail, and only intervention by city police, Monterey county sheriff's deputies, and the Brown Berets prevented a riot and injury to the visitors.

[4][page needed] Chávez was released by the Supreme Court of California on December 23, but the next day called a strike against six additional lettuce growers.

[9][page needed][30] By April 1973, the UFW was "fighting for our lives" and threatening to launch a nationwide boycott of any grower which signed a contract with the Teamsters.

[39] Talks resumed, and a tentative agreement was reached on September 27, 1973 in which the Teamsters again agreed to leave jurisdiction over farm field workers to the UFW.

[41] Newspaper columnists suggested in June that the UFW no longer had any capacity to fight, and by February 1975 had concluded the union had no future.

Although it considered mass picketing, rallies, and more boycotts, the UFW worried that it had lost the support of farm workers and that such events would only highlight the union's political weakness.