Complex sentence: A key factor that hurt John F. Kennedy in his campaign was the widespread prejudice against his Roman Catholic religion; some Protestants, especially Southern Baptists and Lutherans, feared that, if he were elected President, Kennedy would take guidance from the Pope in Rome.
Split into simpler sentences: A key factor that hurt Kennedy in his campaign was the widespread prejudice against his Roman Catholic religion. Some Protestants, especially Southern Baptists and Lutherans, feared that, if he were elected president, Kennedy would take guidance from the pope in Rome.