 As <unk> by Secretary Laird , fallout from the incursion was quick in coming on the campuses of America 's universities , as protests erupted against what was perceived as an expansion of the conflict into yet another country . On 4 May the unrest escalated to violence when Ohio National Guardsmen shot and killed four unarmed students ( two of whom were not protesters ) during the Kent State shootings . Two days later , at the University at Buffalo , police wounded four more demonstrators . On 8 May 100 @,@ 000 protesters gathered in Washington and another 150 @,@ 000 in San Francisco on only ten days notice . Nationwide , 30 <unk> buildings went up in flames or were bombed while 26 schools witnessed violent clashes between students and police . National Guard units were mobilized on 21 campuses in 16 states . The student strike spread nationwide , involving more than four million students and 450 universities , colleges and high schools in mostly peaceful protests and <unk> . 
