The candidates in one of the country's most closely watched Senate races faced off in a final debate on Wednesday night.
Heck was slightly ahead in the polls, but that has changed since he disavowed Republican presidential candidate Donald Trump.
Polls show Rubio leading in the race, but he has also received criticism for sticking to his endorsement of Donald Trump.
McCain said he would not vote for Trump after tape surfaced last week of Trump talking about sexually assaulting women.
Feingold, a Democrat, is taking on incumbent Republican Sen. Ron Johnson in one of this year's most-watched Senate races.
It's the first Senate election for an open seat in California in more than two decades. It's also the first time that both candidates are Democrats.
A tough race between Republican Sen. Mark Kirk and Democratic Congresswoman Tammy Duckworth has gone negative.
After leaving politics for six years, former U.S. Senator of Indiana Evan Bayh enters a tight race for his old Senate seat this summer.
Republican incumbent Roy Blunt is facing Democratic Secretary of State Jason Kander. The two are closer than expected in the polls in what's considered a safe Republican seat.
The state's race is tightening, with two-term Republican incumbent Sen. Richard Burr getting an unexpected challenge from Democrat Deborah Ross.
Here & Now's Meghna Chakrabarti hears the latest about the race from Liz Ruskin, Washington correspondent for Alaska Public Radio.
Republican incumbent Johnny Isakson is facing off against relative unknown Democrat Jim Barksdale, an investment banker, and an independent, Allen Buckley.
Sen. Pat Toomey has not endorsed Trump, and he has said he is troubled by the candidate, but that he is "inclined to support" the party nominee.
Paul is pivoting attention from his failed White House bid to his re-election campaign, where his opponent is openly gay Democrat Jim Gray.