After a photo of Lanny Martinson's dog tag was placed on Facebook and elsewhere, Marines and veterans helped track him down. Martinson lost the tag in Vietnam in 1968. Facebook hide caption

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Democratic presidential candidate George McGovern talks about the bombs being used in Vietnam at a $250-a-person fundraising dinner in Los Angeles on Sept. 27, 1972. AP hide caption

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July 1, 1971: After getting the green light from the Supreme Court, The New York Times resumes publication of its series of articles based on the secret Pentagon Papers. Jim Wells/AP hide caption

itoggle caption Jim Wells/AP