Described by government sources as the largest peacetime search-and-seizure operation in U.S. history, Operation Intercept was launched along the United States—Mexico border in September 1969. This unilateral program was instituted, ostensibly, to halt the flow of MARIJUANA, HEROIN, and other dangerous drugs from MEXICO into the United States. However, Intercept's true goal was not to interdict narcotics but to publicize the war on crime promoted by President Richard M. Nixon, who had taken office the previous January, and to force Mexican compliance with Washington's antidrug campaign. Fashioned by well-meaning but shortsighted law-enforcement officers, who all but totally neglected the State Department and knowledgeable border-state residents, Operation Intercept constituted a classic example of international pressure politics and became a serious incident between Mexico and the United States.

On September 16, 1968, presidential candidate Nixon had pledged to an Anaheim, California, audience that, if elected, he would move against...