August 6 – Resumption of 4-party talks in Paris with David K. E. Bruce now the head of the U.S. delegation.

August 11 – ARVN troops take over the defense of border positions from U.S. troops.

August 22 – Operation Chenla (or Chenla II): A major operation by Cambodian government forces against NVA (PAVN or VPA) and NLF units in eastern Cambodia (around Kampong Thon). It continues until February 1971 and produces limited gains. Reports surface that Khmer Rouge fired on NVA troops from behind, followed by a NVA circular warning its own troops not to fire on the Khmer Rouge.

August 24 – Heavy B-52 bombing raids occur along the Demilitarized Zone (DMZ).

Near 3:40 a.m., the ‘New Years Gang’ on the University of Wisconsin-Madison campus in Sterling Hall detonates a van filled with ammonium nitrate and fuel oil mixture. A researcher, Robert Fassnacht, is killed and three others are injured. The student newspaper, the Cardinal, had published a series of investigative articles making a convincing case that the Army Math Research Center (AMRC) was pursuing research that was directly pursuant to specific U.S. Department of Defense requests, and relevant to counterinsurgency operations in Vietnam. AMRC became a magnet for demonstrations, in which protesters chanted “U.S. out of Vietnam! Smash Army Math!” The Army Mathematics Research Center was phased out by the Department of Defense at the end of the 1970 fiscal year.

August 29 – The Chicano Moratorium: in which 30,000 Mexican-Americans participate in the largest anti-war demonstration in Los Angeles. Police attack the crowd with Billy clubs and tear gas; two people are killed. Immediately after the marchers were dispersed, sheriff’s deputies raid a nearby bar, where they shot and killed Rubén Salazar, KMEX news director and Los Angeles Times columnist, with a tear-gas projectile. The Chicano Moratorium was a movement of Chicano activists that organized anti-Vietnam War demonstrations and activities in Mexican American communities throughout the Southwest and elsewhere from November 1969 through August 1971. “Our struggle is not in Vietnam but in the movement for social justice at home” is a key slogan of the movement. It is coordinated by the National Chicano Moratorium Committee (NCMC) and led largely by activists from the Chicano student movement and the Brown Beret organization. More than 20 local protests are held in Houston, Albuquerque, Chicago, Denver, Fresno, San Francisco, San Diego, Oakland, Oxnard, San Fernando, San Pedro and Douglas, Arizona. Most had 1,000 or more participants.