Washington changes whenever the White House gains a new occupant. When that involves a 47-year-old African-American from Chicago replacing a 62-year-old white Texan, the effect is likely to seem unusually pronounced.

Perhaps the most visible alterations will be in the lower average age of the Barack Obama people, the greater ethnic and gender diversity of the new president’s administration and the fact that it is made up of a more metropolitan and technologically savvy crowd than those they replace.