methodius points out that the first Potter book came out in the year Blair was elected. By a deliciously spooky coincidence the last is going to be published in the year that Blair is pledged to resign.
Fantasy gets to places the realist novel can't reach. At its best it doesn't try to teach us anything (which is why C.S. Lewis and Philip Pullman are lesser writers) it just tips the contents of what Jung called the collective unconscious at our feet. In hindsight it looks as if Rowling were writing a fantasy commentary on the Blair years- the scurvy politicians, the war on terror, the cynical trampling on civil liberties- but, of course, the whole series was planned in detail in advance. Azkaban isn't a reflection on Abu Ghraib and Guantanamo, but a prophecy.
It makes one wonder how much further into the future she has seen.