It is an extraordinary sight to walk into a basic two-room house under a mango tree in rural east Africa and discover what is essentially a shrine to Barack Obama. The small brick house with no running water, a tin roof and roving chickens, goats and cows is owned by Sarah Obama, Barack's 86-year-old step-grandmother. Inside, the walls are decorated with a 2008 Obama election sticker, an old "Barack Obama for Senate" poster on which he has written "Mama Sarah Habai [how are you?]", a 2005 calendar that says "The Kenyan Wonder Boy in the US", and more than a...