For all of the myriad, often-brilliant ways that LIFE covered the world in the middle part of the 20th century, the magazine had a rather fraught relationship with at least one pivotal aspect of the age: namely, the counter-culture of the 1960s, in the U.S. and around the globe.
That a publication of LIFE’s influence and reach only grudgingly paid attention to the Beatles, Bob Dylan, Hendrix and other avatars of the pop-culture revolution might suggest that every aspect of the era’s tumult passed virtually unnoticed. In fact, though, while LIFE might not have covered the Sixties with as much unceasing, breathless fascination as some other periodicals, when it did turn its attention to, say, the explosion of recreational drug use among Americans, its coverage was often admirably even-handed, and something close to exhaustive.
Case in point: In October 1969, LIFE ran a cover story (or rather, a series of stories) under the banner: MARIJUANA: At Least 12 Million American Have Now Tried It. Are penalties too severe? Should it be legalized?
Across 10 full pages, intermingling opinion, photography and reportage, LIFE not only took a hard look at pot smoking in the U.S., but waded deep into the debate—already heated then—of whether or not the country’s draconian marijuana statutes were doing more harm than good.
Part of the coverage, meanwhile, was a thoughtful, full-page essay by a former head of the U.S. Food and Drug Administration (and Bonnie Raitt’s stepfather), Dr. James L. Goddard.
But the most riveting element of the feature in that issue of LIFE was a series of pictures by photographer Co Rentmester made at various points along the U.S.-Mexican border, in which he chronicled the efforts of U.S. Customs agents, through a program dubbed “Operation Intercept,” to stem the flow of weed and other drugs into the States.
The pictures in this gallery, many of which never ran in LIFE, provide a window into the government’s early attempts to patrol an enormous and notoriously porous border, while also reminding us that America’s war on drugs is not only nothing new, but for decades has been a profoundly divisive response to a phenomenon—namely, people getting high—that is never, ever going away.
Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter at @LizabethRonk.