Brown entered his bid for a full term with the edge, given his ability to win crossover Democrats. But Warrenís national fundraising network coupled with the expectation that President Barack Obama would carry the state handily gave Democrats one of their best offensive opportunities.
The Florida Senate race was called quickly after polls closed at 8 p.m., with Sen. Bill Nelson (D) holding on against Rep. Connie Mack IV (R). Nelson had been solidly favored for a few months, even as the presidential race was tight.
Elsewhere, polls closed in Connecticut and Pennsylvania, where two Democratic-held seats attracted outside spending late in the election cycle. Pennsylvania Sen. Bob Casey (D) faced a wealthy challenger in Tom Smith (R) and a far more competitive race than had been predicted. That state also tightened late in the presidential contest.
In Connecticut, Republican Linda McMahon, the former WWE CEO and the 2010 Senate nominee, against invested considerable personal funds in the race and gave Democrats a scare in a state Obama should win by a wide margin. Still, Rep. Christopher Murphy (D) had the late edge.
Sens. Joe Manchin (D-W.Va.) and Bernie Sanders (I-Vt.) were the first Senators whose re-elections were called. Joining them in the 8 oíclock hour were Sens. Tom Carper (D-Del.), Sheldon Whitehouse (D-R.I.), Bob Corker (R-Tenn.) and Benjamin Cardin (D-Md.).
7:17 p.m. | Democrats entered Election Day with the edge in the battle for the Senate, and a few states with early poll times should give strong clues toward whether the party will hold its majority for another two years.
At 7 p.m. EST all polls were closed in Virginia and Indiana, and polls will close in Ohio at 7:30 p.m. Most polls will have closed in Florida by 7 p.m. as well, but much of the Panhandle allows voting until 8 p.m.
With Democrats currently holding a 53-47 majority, the path for Republicans would narrow considerably if former Virginia Gov. George Allen (R) does not reclaim his former seat in his race against former Gov. Tim Kaine (D).
Meanwhile, GOP hopes would be all but dashed if Indiana state Treasurer Richard Mourdock (R) loses his bid for the open seat after defeating Sen. Dick Lugar in the GOP primary in May. Roll Call rates both races as Tossups.
Allen and Kaine are vying for the seat of retiring Sen. Jim Webb (D), who defeated Allen in 2006. The race is inextricably tied to the presidential contest, which was also a Tossup in the closing days of the campaign.
Mourdock faces Rep. Joe Donnelly (D) in a surprisingly competitive race that took a turn for the worse for Republicans following the primary. Some late polls gave Donnelly the lead, but this is a state that GOP presidential nominee Mitt Romney should win by a significant margin.
In Ohio, Sen. Sherrod Brown (D) is favored in his first bid for re-election. Republicans are counting on a strong showing from Romney in one of the most important presidential contests to help push state Treasurer Josh Mandel (R) over the finish line.
Several more close contests will still be to come after the 7 oíclock hour, but these three races can set the tone and give political observers a taste of whatís to come.