Can we draw the following hypothesis from the context? 

Context:

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.

Hypothesis: The US made efforts to support Cuba and no desire to slander Cuba.