US President Barack Obama and First Lady Michelle Obama (2ndR)with daughter Malia (L), Sasha(C) and mother-in-law Marian Robinson(R) visit the Martin Luther King Jr. Memorial October 16, 2011 in Washington, DC. Obama hailed the “moral imagination” and “hopeful vision” of Martin Luther King on Sunday at a Washington ceremony attended by thousands to dedicate a monument to the slain civil rights icon. AFP PHOTO/Mandel NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)