Though President Barack Obama and first lady Michelle still have two years left in the White House, their foundation has come up with a bold slogan for their next chapter: “Eight years is only the beginning.” When they leave on Jan. 20, 2017, Obama will be only 55 and his wife, who turned 51 on Jan. 17, will have just celebrated her 53rd birthday. Not that I ever doubted it, but the Chicago-based Barack Obama Foundation‘s revamped website, which went live Friday, makes it clear the Obamas intend to maintain a robust public presence in the decades to come. The...