Along with the 1944 Education Act and his reforms as Home Secretary, John Campbell sees Butler's greatest achievement as the "redefine(ing of) the meaning of Conservatism" in Opposition, encouraging the careers of talented younger men at the Research Department (Heath, Powell, Maudling, Macleod, Angus Maude, all of whom entered Parliament in 1950) ensuring Conservative acceptance of the welfare state and a commitment to keeping unemployment low. Macmillan acknowledged Butler's role in his memoirs, whilst stressing that these were the very policies he had promoted in vain in the 1930s. Butler enjoyed 26.5 years in office, equalled only by Churchill in the twentieth century.