Complex sentence: It was decided that he could not return to South Africa, the fear being that his views would contaminate the minds of the members in that country with Trotskyite ideas, but a compromise was suggested with the United States seen as a place he could be rehabilitated.
Split into simpler sentences: It was decided that he could not return to South Africa, for fear that his views would contaminate the minds of the members in that country with Trotskyite ideas. A compromise was suggested with the United States seen as a place he could be rehabilitated.