COLUMBUS, OH - NOVEMBER 4: Supporters of Democratic presidential nominee U.S. Sen. Barack Obama (D-IL) celebrate as they hear Pennsylvania has been called for their candidate at the Ohio Democratic Party poll watching event in the downtown on November 4, 2008 in Columbus, Ohio. After nearly two years of presidential campaigning, U.S. citizens went to the polls today to vote in the election between Democratic presidential nominee U.S. Sen. Barack Obama (D-IL) and Republican nominee U.S. Sen. John McCain (R-AZ).