ST. PAUL, MN - JUNE 3: Tunnel entrance to the Xcel Energy Center where Democratic presidential hopeful Sen. Barack Obama (D-IL) addressed a rally at the Xcel Energy Center June 3, 2008 in St. Paul, Minnesota. Obama clinched the Democratic presidential nomination following today's primaries in South Dakota and Montana, although his rival Sen. Hillary Clinton (D-NY) has not yet conceded the race. (Photo by Joshua Wanyama)