 Complete the following phrase:  Nikita Khrushchevs denunciation of Stalinism at the 1956 Party Congress silenced Robeson on Stalin, although Robeson continued to praise the Soviet Union. In 1956, after public pressure brought a one-time exemption to the travel ban, Robeson performed two concerts in Canada in February, one in Toronto and the other at a union convention in Sudbury, Ontario. That year Robeson, along with close friend W.E.B. Du Bois, compared the 