Lawson was one of the Hollywood Ten, the first group of American film industry professionals to be blacklisted by Congress during the 1950s McCarthy era's investigation of communist influence in Hollywood. He and his colleagues refused to testify; he was convicted of contempt of Congress and served a year in prison. He moved to Mexico, where he wrote some books about theater. After returning to the US, he taught at some universities in California. Using a pseudonym, he wrote the screenplay for "Cry, the Beloved Country" (1951), an adaptation of Alan Paton's novel about South Africa that was critical of apartheid.