North Dakota: Heidi Heitkamp (D) vs. Rep. Rick Berg (R)
Open seat -- Sen. Kent Conrad (D) is retiring
Former state Attorney General Heidi Heitkamp gives Democrats their best opportunity to keep the seat of retiring five-term Sen. Kent Conrad. Republicans hope first-term Rep. Rick Berg will repeat the party's success of 2010, when they took over retiring Democrat Byron Dorgan's seat.
The state has a history of split-ticket voting, giving Heitkamp an opportunity to show her independence from national Democrats. She's publicly disagreed with Barack Obama on issues like energy, which she points to as evidence she won't be a rubber stamp. She enjoys high favorables and solid support from Republican ticket-splitters and has hammered Berg for his connection to a controversial real estate company.
With the lowest unemployment rate in the country, North Dakotans have their choice between two candidates with strong statewide appeal. This race will remain close until Election Day.
Ohio: Sen. Sherrod Brown (D) vs. Josh Mandel (R)
UPDATE: Sherrod Brown (D) is predicted to beat Josh Mandel.
Amid the backdrop of what is arguably the nation's most competitive presidential battleground contest, first-term Senate incumbent Sherrod Brown hopes to prove that the Democratic wave that helped carry him into office in 2006 wasn't a fluke. Brown, who has a voting record the National Journal classified as one of the most liberal in the Senate, made a ripe target for Republicans looking for a pickup opportunity.
But in the home stretch of the 2012 campaign, Ohio remains conspicuously off the list of the most vulnerable Democratic-held seats. The Republican nominee is Josh Mandel, the 35-year-old state treasurer and Marine Corps veteran. Mandel has kept pace with Brown in terms of fundraising, but he continues to trail the incumbent by around 10 points in several independent polls from September and October.
Brown is far from having the race sewn up, especially with the daily volatility at the top of the ticket, but he has a leg up as the race enters its final days.
Pennsylvania: Sen. Bob Casey (D) vs. Tom Smith (R)
UPDATE: Sen. Bob Casey (D) defeats Tom Smith.
Recent polls have given Republicans hope where they previously had little. As Democratic Sen. Bob Casey's lead over Republican businessman Tom Smith began to tighten, the incumbent began actively campaigning across the state -- something he previously hadn't been doing.
Though Republicans have an opening now, Casey still enters the final stretch with the advantage. The state has not emerged as a contested presidential battleground and a strong showing by Barack Obama here could help Casey beat back this unexpected and late-breaking challenge.
Rhode Island: Sen. Sheldon Whitehouse (D) vs. Barry Hinckley (R)
UPDATE: Sheldon Whitehouse wins a second term.
Democrat Sheldon Whitehouse is a safe bet to win a second term in November. He faces Republican businessman Barry Hinckley.
UPDATE: Bob Corker (R) wins senate seat.
Unlike the tough battle he had in 2006 to take the seat, Republican Bob Corker should easily win a second term in November. He faces Democrat Mark Clayton, whose candidacy has been disavowed by the Tennessee Democratic Party for his involvement with an anti-gay rights group.