Open seat -- Sen. Jon Kyl (R) is retiring
This race turned more competitive than originally expected. Democratic nominee Dr. Richard Carmona, a Vietnam veteran and a former U.S. surgeon general under President George W. Bush, proved to be a formidable opponent to six-term Rep. Jeff Flake, whose tough August primary for the GOP nomination left him bruised as he began the general election.
Tightening polls caused both campaigns to go negative, with Flake accusing Carmona of having anger issues over an incident in which a former HHS official accused him of banging on her door in the middle of the night and scaring her family (Carmona denied the incident ever occurred). Carmona accused Flake of not supporting veterans as a congressman (Flake said Carmona is cherry-picking votes and not looking at his entire record).
Democrats thought their candidate's strengths and the state's growing Hispanic population will lead to their party's first successful Senate election since 1988. But Republicans pointed to no significant changes in Hispanic voting records, Flake's endorsements from Sens. Kyl and John McCain, and the state's traditional GOP support as reasons for a Flake victory.
Connecticut: Rep. Chris Murphy (D) vs. Linda McMahon (R)
CNN projection: Rep. Chris Murphy wins
In the closely watched senate race in Connecticut, Democratic Rep. Chris Murphy defeated Republican nominee and professional wrestling executive Linda McMahon, according to a CNN projection.
Murphy will take over the Senate seat being vacated by retiring Sen. Joe Lieberman, an Independent who sided with Democrats.
His win preserves a seat for Democrats who feared losing it to the wealthy McMahon, who spent over $90 million in the last two elections to try to win a Senate seat.
The race was marked by heavy negative advertising.
Indiana: Richard Mourdock (R) vs. Rep. Joe Donnelly (D)
CNN projection: Rep. Joe Donnelly wins
Democrats scored a major upset in the Indiana Senate race, scooping up a seat in the deeply red state Republicans had expected to hold.
The campaign appeared to turn for the Democrats after the GOP candidate made controversial comments about rape during a televised debate.
Mourdock, the State Treasurer, was backed by both tea party supporters and the Republican establishment when he defeated in the primary longtime GOP moderate Sen. Richard Lugar. When that happened, Democrats thought Donnelly, who is conservative and pro-life, had an outside chance of winning the seat.
Mourdock gave Donnelly an opening when during a debate he defended his opposition to abortion even in the case of rape because, "I think even when life begins in that horrible situation of rape, that is something God intended to happen." Top Democrats and Republicans criticized the remark and within days, Donnelly took a substantial lead in one respected Indiana poll.
Maine: Charlie Summers (R) vs. Cynthia Dill (D) vs. former Gov. Angus King (I)
CNN projection: Former Gov. Angus King wins
Former Gov. Angus King, an Independent, steadfastly has refused to say if he will organize with Democrats or Republicans when he gets to Washington. If the Senate is narrowly divided after Tuesday's election, he could determine which party gets majority control.
King will replace Sen. Olympia Snowe, herself an independent-minded Republican who stunned her colleagues this year when she announced she would retire from the Senate, which she complained has become increasingly partisan.