Possible Clues:

• 44th U.S. president
• President who appointed two women to the Supreme Court
• 2008 "Yes We Can" sloganeer
• See 3-Down
• President who appointed Justice Kagan
• 21st-century president with a Nobel Peace Prize
• Senator Barack
• 2009 Nobel laureate
• Appointer of Justice Kagan
• Illinois Senator Barack