Dec. 7, 1941: The Japanese attack Peal Harbor, pulling the United States into World War II. A 1940 U.S. census counted 377,433 people born in Mexico.

February 1942: U.S. and Mexican governments agree to begin formal talks leading to a guest-worker program.

May 1942: U.S. labor studies find that in the run-up to WWII and immediately after Pearl Harbor, 1 million rural workers have moved to the military and factory jobs in major U.S. cities. Farmers alert the U.S. federal government that they face harvest-time disasters if replacement workers are not brought in.

Aug. 24, 1942: U.S. and Mexico sign an executive agreement to recruit Mexican temporary workers for U.S. farms, with transportation and other costs to be borne by the U.S. government. Mexico refuses to allow workers to be recruited for Texas farmers because of a history of discrimination against Mexicans in the state. The U.S. promises that braceros will not be mistreated.

Sept. 29, 1942: The first group of Mexican braceros reports for work in Stockton, Calif. Days after a celebratory picnic sponsored by local farmers, the braceros go on strike, complaining that the pay for harvest work is less than promised. Farmers relent and raise the pay.

Jan. 1, 1943: U.S. War Manpower Commission tells the State Department that the railroad industry faces a severe labor shortage, touching off talks with Mexico to expand the bracero program.

February 1943: Mexico suspends bracero recruiting, citing poor treatment of the 4,200 workers who had ventured north in the fall of 1942. The U.S. promises to improve conditions for braceros, and a new agreement is signed. In all of 1943, 53,000 braceros go to U.S. farms.

May 14, 1943: 760 workers leave Mexico City by rail, bound for Texas, where they are assigned to work on various U.S. railways.

June 21, 1943: The U.S. Office of Labor is established to monitor the bracero agreement.

December 1943: The Mexican Labor Ministry reports that 76,184 men worked in the United States as braceros that year.

Oct. 31, 1944: Mexican doctors finish physical examinations of 69,455 workers; 1944 ends with the highest number of wartime braceros north of the border – 118,182.

February 1945: Mexican railroads report the heaviest monthly traffic of northbound braceros – 8,000.

Sept. 2, 1945: Japan officially surrenders, ending World War II. At the time, more than 100,000 braceros are working in the U.S.

Aug. 24, 1945: Last rail cars of Mexicans headed for railroad jobs cross into Texas. That part of the bracero program is suspended.

September 1945: U.S. count shows that 300,000 Mexican men worked as braceros during World War II. Their total earnings during the war years were $228 million (in 1945 dollars).

March 1946: U.S. farmers pressure the federal government to continue the agricultural portion of the bracero program, citing the loss of workers to postwar urban expansion, and increased food demands at home and around the world. At least 26,214 Mexicans work on U.S. farms in 1946.

May 14, 1946: The U.S. Embassy in Mexico relays a U.S. State Department desire to discontinue the 10 percent wage deduction for braceros.

Spring 1946: After four years of illegal recruiting of Mexican workers by Texas farmers, Mexico relents and allows braceros to officially work in the state. Mexico turns around and removes Idaho from the approved states, citing poor treatment of Mexicans in that state. The Idaho Legislature had created rules forcing braceros to stay on the job or face arrest and deportation – and forced, unpaid labor while awaiting trial.

Spring 1947: U.S. and Mexico alter the bracero pact, dropping government recruiting in Mexico and turning that over to private farm interests, which would then venture to Mexico to hire workers.

Feb. 6, 1947: Mexico's Banco Nacional de Credito Agrícola, one of two principal holders of bracero savings, files an internal audit showing that 12 million pesos (about $4 million in 1947 dollars) – savings funds belonging to braceros – has instead been used to fund "day-to-day operations" of the bank. The audit does not say whether that money has been returned to braceros.

February 1948: A new U.S.-Mexico bracero deal reinstates the 10 percent wage deduction.

September 1948: Mexico reports about 20,000 braceros working in the United States.

October 1948: The 10 percent wage deduction is once again suspended.

Spring 1955: Ernesto Galarza, a former Pan-American Union official, publishes Strangers in Our Fields, a blistering account of how safeguards in bracero contracts were constantly violated.

Summer 1959: Mr. Galarza and Cesar Chavez begin advocacy work in California bracero camps to expose poor living and working conditions. Bracero registry reaches its peak – 430,000 working in the United States.

Summer 1963: Labor Secretary Arthur Goldberg reflects the Kennedy administration's dim view of the bracero program. That results in U.S. congressional action allowing just one more year of bracero recruiting