Even though Republicans hold the lion's share of Senate open seats this cycle (seven to three), both parties hold an equal number of spots in the latest Hotline list of the 10 most vulnerable seats. The good news for Democrats is that Barack Obama carried all five of their vulnerable states last fall. And, of the five GOP seats up for grabs, two (Ohio and New Hampshire) went for Obama and one, Missouri, was only narrowly carried by John McCain.
Even so, if the president and the Democratic-controlled Congress are unpopular next year, the president's 2008 performance won't mean all that much.
While these rankings will shift around between now and November 2010, it's more than likely that these 10 races are going to determine whether Democrats are able to hold their supermajority for another two years.
1. Connecticut -- Christopher Dodd, D (no change)
Dodd's fortunes may have seen a slight uptick over the past couple months, largely due to the increasingly fractious nature of the GOP primary. Any incumbent polling around 40 percent remains highly endangered, but even so, in the last few months we've seen Dodd's favorable job ratings go up and his disapproval ratings go down, suggesting that current negative opinions about him aren't set in stone.
2. Illinois -- open seat, D (no change)
If there was one ranking that generated controversy last time, it was Illinois. Surely, the critics suggested, Obama's home state would never replace him with a Republican. In the end, the true-blue nature of Illinois -- along with an expected serious financial investment from a White House laden with Chicagoans -- would surely assert itself come November 2010. Right? We're simply not convinced that the field of Democratic candidates -- with the possible exception of former Chicago Inspector General David Hoffman -- can present the sort of "outsider" credentials to avoid being lumped (fairly or not) with Rod Blagojevich, et al. Plus, it's hardly unusual for a state's voters to develop a "throw the bums out" mentality when one party has overstayed its welcome. Even so, can Rep. Mark Kirk (R) convince voters that his nine years in D.C. qualify him as the heir to the "outsider" mantle?
3. Missouri -- open seat, R (no change)
With both Secretary of State Robin Carnahan (D) and Rep. Roy Blunt (R) focused on third-quarter fundraising, this contest has been pretty sleepy. For now, the race is being defined by Blunt's record in D.C. and Carnahan's family name. Advantage: Carnahan. She has so far avoided being pinned down on contentious issues but won't be able to do so forever. Will she be able to continue to define herself as a "Carnahan Democrat," or will the national Democratic label define this contest?
4. Ohio -- open seat, R (no change)
By the time third-quarter Federal Election Commission reports are due Oct. 15, we'll have a better idea of whether the race for the Democratic nomination will be a barn-burner or fizzle out. If Secretary of State Jennifer Brunner doesn't close the fundraising gap with Lt. Gov. Lee Fisher, it means Fisher's not only the frontrunner but will likely be able to save up his cash for November. Former Rep. Rob Portman (R) has trailed slightly in the polls, but practically everyone agrees this race is a pure toss-up and could end up the bellwether Senate race of 2010.
5. New Hampshire -- open seat, R (no change)
National Republicans like former Attorney General Kelly Ayotte's profile -- a woman without a voting record or ties to Bush. But it hasn't been enough to deter others from sniffing around a primary challenge. To be sure, sometimes primaries can help to battle-harden novice candidates like Ayotte, but with New Hampshire's September 2010 primary date, that wouldn't leave her much time to prepare for November. For his part, Rep. Paul Hodes (D) is working to protect himself from attacks as a D.C. insider. He was one of just a handful of Democrats to vote against the reprimand of South Carolina Republican Joe Wilson and is leading the charge in the House against extending the Troubled Asset Relief Program.
6. Colorado -- Michael Bennet, D (not ranked)
Although Bennet is off to a strong fundraising start, polling suggests this is essentially an open seat. Voters seem to know very little about either Bennet or his GOP opponents, suggesting that the national political climate is going to have an oversized influence on this contest. And recently announced bids by former state House Speaker Andrew Romanoff (D) and former Lt. Gov. Jane Norton (R) give Bennet two potentially tough opponents that he would like to have avoided.
7. Nevada -- Harry Reid, D (not ranked)
The long-held truism that you can't beat someone with no one may be turned on its head here. While Majority Leader Reid has several things going for him, including a huge war chest and voter registration stats that lean in his favor, polling suggests a majority of Nevadans have soured on him. And, while big-name Republicans have passed on the race, Reid is struggling in matchups against virtual no-name candidates. A Daschle-Thune race this isn't. Betting against a guy with $7.3 million in the bank is normally a bad idea, but the odds that Reid is put to the test this year are good.
8. Pennsylvania -- Arlen Specter, D (was No. 6)
Given the nature of the state and Republican Pat Toomey's low profile, one has to give the edge to either Specter or Rep. Joe Sestak (D) come November 2010. Still, Specter is probably the more vulnerable in November. And a bruising Democratic primary gives Toomey the opportunity to make this race a referendum on the nominee's shortcomings instead of his own. Toomey's role as the former head of the conservative Club For Growth gives Democratic opposition researchers lots to pore over for politically damaging quotes.
9. Kentucky -- open seat, R (was No. 7)
It's certainly true that Kentucky is an unlikely state to elect a Democratic senator in the midterm of a Democratic president. Even so, Rand Paul's fundraising success indicates he will be more than a nuisance challenger to GOP frontrunner Trey Grayson, the secretary of state. And Kentucky voters have shown a willingness to elect Democrats to other statewide offices.
10. Louisiana -- David Vitter, R (no change)
Vitter's vulnerabilities are obvious, but... perhaps a bit too obvious? It can sometimes be very risky to remind voters what they already know but are eager to forget. Rep. Charlie Melancon (D) certainly has a chance, but his prospects would improve greatly if Vitter gets a primary challenger that saves Melancon from having to make his case so soon. Plus, do we really think a state that gave Obama just 40 percent is going to perform better for Dems in an off-year election?
Quinn McCord, The Hotline's managing editor, contributed to this column.