UK Foreign Office report claimed that the rioting had been organized by 100 members of the German SDS who were "acknowledged experts in methods of riot against the police." In March, Gallup poll reported that 49% of respondents felt involvement in the war was an error. April 17 – National media films the anti-war riot that breaks out at Columbia University. The over-reaction by the police at Columbia is shown in Berlin and Paris, sparking reactions in those cities. On April 26, 1968, a million college and high school students boycotted class to show opposition to the war. April 27 – an anti-war march in Chicago organized by Rennie Davis and others ended with police beating many of the marchers, a precursor to the police riots later that year at the Democratic Convention. During the 1968 Democratic National Convention, held August 26 – August 29 in Chicago, anti-war protesters marched and demonstrated throughout the city. Chicago mayor Richard J. Daley brought to bear 23,000 police and National Guardsman upon 10,000 protesters. Tensions between police and protesters quickly escalated, resulting in a "police riot" and the chant by protesters "The whole world is watching". Eight leading anti-war activists were indicted by the U.S. Attorney and prosecuted in 1969 for conspiracy to riot; the 1970 convictions of the Chicago Seven were subsequently overturned on appeal. August – Gallup poll shows 53% said it was a mistake to send troops to Vietnam. Among the academic or scholarly groups was the Committee of Concerned Asian Scholars, founded in 1968 by graduate students and junior faculty in Asian studies. 1969 March polls indicated that 19% of Americans wanted the war to end as soon as possible, 26% wanted South Vietnam to take over responsibility for the war from the U.S., 19% favored the current policy, and 33% wanted total military victory. In March, students at SUNY Buffalo destroyed a Themis construction site. On March 5, Senator J. William Fulbright was prevented from speaking at the first National Convocation on the Challenge of Building Peace by members of the Veterans and Reservists to End the War in Vietnam. On April 6, a spontaneous anti-war rally in Central Park was recorded and later released as Environments 3. On May 22, the Canadian government announced that immigration officials would not and could not ask about immigration applicants' military status if they showed up at the border seeking permanent