Possible Clues:

• ''The Audacity of Hope'' author
• Two presidents ago
• Senator who wrote 'Dreams From My Father'
• Grammy-winning president
• Kagan's appointer
• Winner of 2008
• President born furthest from Washington, D.C.
• ''Dreams From My Father'' author
• Appointer of Kagan and Sotomayor
• President between Bush and Trump