Castro's successful visits to Harlem and the Bronx, his speech to the United Nations General Assembly, and the October 21 march of 3,000 against U.S. policy and subsequent picket lines at Cuba's UN mission in defense of the revolution - all these events dealt blows to the U.S. government's unceasing efforts to isolate and slander Cuba.
Does this next sentence follow, given the preceding text?
Castro would never come back after the speech.
It's impossible to say