Obama supporters react as President Barack Obama was declared the winner Tuesday, during the Nevada State Democratic Party gathering at the Mandalay Bay Resort and Casino in Las Vegas. John Gurzinski/AP hide caption

itoggle caption John Gurzinski/AP

Republican presidential nominee Mitt Romney pauses while speaking at a campaign rally at the Patriot Center at George Mason University in Fairfax, Va., on Monday. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

Professor John Straayer has taught political science at Colorado State University in Fort Collins for 46 years. He is not surprised that this year's race in Colorado is among the tightest in the nation. Becky Lettenberger/NPR hide caption

itoggle caption Becky Lettenberger/NPR