Complex sentence: In later life Macmillan was open about his failure to read Eisenhower's thoughts correctly and much regretted the damage done to Anglo-American relations, but always maintained that the Anglo-French military response to the nationalisation of the Canal had been for the best.
Split into simpler sentences: In later life Macmillan was open about his failure to read Eisenhower's thoughts correctly and much regretted the damage done to Anglo-American relations. However he always maintained that the Anglo-French military response to the nationalisation of the Canal had been for the best.