Complex sentence: Butler's close association with appeasement was often held against him later in his career, more so than against Lords Home or Hailsham, his rivals for the party leadership in 1963, who had been more junior.
Split into simpler sentences: Butler's close association with appeasement was often held against him later in his career. Appeasement was held against him more than against Lords Home or Hailsham, his rivals for the party leadership in 1963, who had been more junior.