Brooke felt that Alexander needed an able chief of staff "to think for him", while Montgomery (Alexander's subordinate in Africa and Italy) claimed to think of Alexander as "incompetent" and success was attained in Tunisia only because Montgomery lent Lieutenant-General Brian Horrocks, the commander of IX Corps, to organise the coup de grace. However, Harold Macmillan was impressed by Alexander's calm and style, conducting dinners in his mess like those at an Oxbridge high table, discussing architecture and the campaigns of Belisarius, rather than the current war. Macmillan thought Alexander's urbane manner and willingness to discuss and compromise were a sensible way to maintain inter-Allied cooperation, but Alexander's reserve was such that some thought him empty of strategic ideas and unable to make decisions. Graham and Bidwell, however, wrote that Alexander's impenetrable reserve made it hard to judge whether or not he had any military ideas, but that he was "unable or unwilling" to assert his will over his army commanders, and that Mark Clark, who often referred to him scornfully as a "peanut" and a "feather duster", exploited this weakness.