State of the Senate races
The debate continues about whether Republicans can wrest control of the Senate from the Democrats on Election Day and the reality is this: there are currently 12 top battleground Senate states and a net swing of 4 seats would put the GOP back in charge of the Senate. (Just three will swing it if Mitt Romney wins the White House because a Vice President Paul Ryan would break 50-50 ties in the chamber).
The top races that will decide control are in Massachusetts, Montana, North Dakota, Wisconsin, Virginia, and Connecticut (all of which are currently tossups that could go either way) along with Maine, where an independent may win. A few Senate battlegrounds are currently leaning to one side: two are leaning Democratic (Missouri and Hawaii) and three are leaning Republican (Indiana, Arizona, Nevada).
The current number of competitive races is a little larger than many had expected earlier this year, but that's not unusual for Senate races - voters often pay more attention to the presidential race first and tune in to the Senate late. And things will surely shift again, for the same reasons.
A common theme to note: Many of these contests feature Democrats running in Republican "red" states or Republicans running in a blue one. Because of that, if there is one kind of "swing voter" for the Senate, it is surely the "ticket-splitter" - the person who'll consider voting for a different party for President and Senate.
Top Senate Battlegrounds
Tossups: Massachusetts, Montana, North Dakota, Wisconsin, Virginia, Connecticut, Maine
Lean Rep: Indiana, Arizona, Nevada
Lean Dem: Missouri, Hawaii
Tossups
Massachusetts: Tossup
Elizabeth Warren (D) vs. Sen. Scott Brown (R)
Perhaps the most-watched race in the nation. Brown has run as a moderate - he needs the lion's share of independents and some crossover Democrats to win - while Elizabeth Warren has tried to nationalize the race in trying to tie Brown to DC Republicans. Obama could win perhaps 60% of the statewide vote so Brown hopes Obama's coattails are short.
Montana: Tossup
Sen. Jon Tester (D) vs. Denny Rehberg (R)
A race heavily focused on state-level issues with both candidates trying to distance themselves from Washington - though they both serve there. Tester - who barely won this seat by just a few thousand votes in 2006 - now faces a tough road running on the same ticket as an unpopular President. Although a Congressman, Rehberg has the advantage of also being a statewide officeholder, as Montana has just one Representative, so name ID was never a problem for him.
North Dakota: Tossup
(Open seat - Democratic held - Sen. Kent Conrad retiring)
Heidi Heitkamp (D) vs Rick Berg (R)
The GOP started eyeing a pickup in this Republican state as soon as the seat opened, and the partisan makeup of the state still favors them. But Democrats have made it interesting with a strong challenge from former state AG Heidi Heitkamp, who is running (like other red-state Democrats) at a distance from Washington and President Obama, and trying to focus on state issues and personal appeal. North Dakota's voters have often split their tickets for Senate and President, but in this heavily partisan era and without a longtime incumbent Democrat, the question is whether enough of them will really do so.
Wisconsin: Tossup
(Open seat - Democratic held - Kohl retiring)
Tammy Baldwin (D) vs. Tommy Thompson (R)
Thompson is a former Governor with potential crossover appeal - in a closely contested Presidential race he has the potential to draw enough independents and conservative Democrats even if Obama does squeak out a win in the state. But Baldwin faced no primary opposition and has a solid base in the Democratic strongholds.
Virginia: Tossup
(Open seat - Democratic held - Webb retiring)
Tim Kaine (D) vs. George Allen (R)
A race that will probably track closely with the Presidential race in the state and depend heavily on turnout. With two well-known statewide candidates, a matchup of ex-Governors, there isn't much voters don't know about them.
Connecticut: Tossup
(Open seat - Sen. Joe Lieberman (I - D) is retiring)
Chris Murphy (D) vs. Linda McMahon (R)
Not one that we initially expected to be a close race, but more recent polls show this tight; CT is a reliably blue state, but McMahon has had a lead or been almost even in her second run at a Senate seat. There will be plenty of focus on McMahon's money and spending, but she's running with a consistent jobs & economic theme. The electorate won't be as favorable to a Republican in 2012 as it was in 2010, when she fell short, but with a statewide profile now, she can win if she gets enough conservative Democrat and moderate support this time around.
Maine: Tossup
(Open seat - Republican held - Sen. Olympia Snowe retiring)
Cynthia Dill (D) vs. Charlie Summers (R) vs. Angus King (I)
This is an unusual kind of "tossup" -- the suspense here is only somewhat in the voting outcome. Former Governor Angus King has a lead in the polls running as an Independent, though there are some signs it won't be a cakewalk at all. He's faced strong campaigning from the Republicans and Charlie Summers. But if King does win, it isn't known which party he'd caucus with in Washington.
Senate Battlegrounds that lean: races that could still go either way, but where one side has an edge
Missouri: Leans D
Sen. Claire McCaskill (D) vs. Todd Akin (R)
Incumbent Democrat Claire McCaskill had seemed headed for defeat in red-state Missouri, but the controversy surrounding Republican nominee Todd Akin, and the national party's distance from him, has turned this into a really competitive race. Polling has McCaskill with a narrow edge.
Indiana: Leans R
(Open - Republican held - Sen. Richard Lugar was defeated for re-nomination)
Joe Donnelly (D) vs. Richard Mourdock (R)
This is longtime Senator Richard Lugar's seat - but Lugar is leaving involuntarily, defeated in the Primary last spring by the Tea Party movement and State Treasurer Richard Mourdock.
Lugar would have held the seat easily in the General Election, but polls have this race tighter than expected. It's still a Republican-leaning state, so Mourdock has to be favored - but if he loses, especially as Romney is favored to carry the state, it becomes a broader story about whether Tea Party candidates can consistently attract enough moderates to win in a General.
Hawaii: Leans D
(Open - Democratic held - Akaka retiring)
Mazie Hirono (D) vs Linda Lingle (R )
Politically, it's really blue Hawaii... the President is expected to do very well, so even the slightest coattails would help Hirono. It may still not be a cakewalk for Democrats. Lingle is a former Governor, though, and also running at a distance from the national party and focusing on state issues instead of national partisan politics.
Arizona: Leans R
(Open - Republican held - Kyl retiring)
Jeff Flake (R) vs Richard Carmona (D)
This one has long been expected to be a win for Republicans - but some recent polling has it closer than many thought. Democrats liked their chances with the selection of Carmona, the former Surgeon General, though it is fundamentally a Republican-leaning state.
Nevada: Leans R
Sen. Dean Heller (R) vs. Shelley Berkley (D)
In a closely contested state, the incumbent has the lead in the polls.
Note that other states could come into play - that's especially true in Senate races where voters don't always pay attention until the very end. We'll also keep an eye on Ohio and Florida, but those look reasonably likely for Democratic incumbents for now.
Joe Williams of the CBS News Election Unit contributed to this report
