Early returns show Democrats holding on to Senate seats in Florida, West Virginia and Massachusetts, Republicans holding in Maine and Indiana and an independent, who is likely to vote along the same political lines as Democrats, in Vermont.

Battleground states Montana, Virginia and Missouri remain too close to call, but Democrats were dealt a blow in their efforts to win a Senate majority when Republican Bob Corker defeated Rep. Harold Ford Jr., Tenn., in Tennessee. Corker won by 3 percent.

In Pennsylvania, Democrat Robert Casey Jr. is projected to defeat long-time Republican incumbent Sen. Rick Santorum, the third-highest ranking U.S. Senator.

In Ohio, incumbent Republican Mike DeWine is projected to lose to Democratic challenger Sherrod Brown. That indicates a one-seat net gain for Democrats thus far.

Independent incumbent Joe Lieberman is projected to win in Connecticut by about a 10-point margin over Democrat candidate Ned Lamont. Lieberman, long-time Democrat, lost in the Connecticut Democratic primary, and is likely to vote with Democrats.

In Vermont, independent Bernard Sanders is likely to defeat Republican Richard Tarrant. Sanders will occupy the seat vacated by Sen. James Jeffers, also an independent. Sanders is expected by many pundits to vote much like his predecessor, who often aligned with Senate Democrats.

In Rhode Island, Republican incumbent Lincoln D. Chafee will likely be defeated by Democrat Sheldon Whitehouse, the third party switch of the night, according to proprietary exit polling data.