Well, there are all of about five hours left in September, and I haven’t gotten the monthly Senate rankings out to you. What follows is an abbreviated version; it’s been a relatively dull month, besides, for movement in most of these Senate races. We’ll be back with a more full-fledged update in October.
Races are ranked in order of their likelihood of changing parties (by November 2010, accounting for all factors such as potential retirements, primary challenges, and so forth).
Likelihood of party switch has increased since last month‘s rankings.
Likelihood of party switch has decreased since last month.
1. Missouri (R-Open) — Rasmussen has the race tied which is not bad news for Robin Carnahan considering that they’ve generally had pessimistic numbers for Democrats in this cycle. Not sure that Roy Blunt says “change” in what might be a fairly anti-establishment election. Then again, neither does Carnahan — but you’d rather be a credible state-level official in this election than a member of Congress.
2. 
Nevada (D-Reid) — He’s now tied with or trailing what amount to generic Republican opponents in many polls. He’ll have money and organizational firepower, but not sure if it will be enough — he’s a big target — and I don’t see what narrative angle he’s going to take to turn things around.
3. Ohio (R-Open) — Numbers have been fairly static, generally continuing to show the Democrats in a slightly stronger position than Rob Portman. As with Roy Blunt, I’m not sure that Portman is the right kind of challenger for this cycle, although certainly he’ll be formidable organizationally. The top four races are very close and hard to distinguish from one another.
4. 
Connecticut (D-Dodd) — Some slight abatement of his negatives in the latest Quinnipiac poll, although Rob Simmons, the most electable of his challengers, appears to be cleaning up in the GOP primary field.
5. 
Colorado (D-Bennet) — Jane Norton’s entry into the race creates real problems for Bennet. I may be jumping the gun since there’s only been one poll with Norton listed (Rasmussen, which showed her with a 9-point lead), but this is a state that has grown more skeptical than most of Obama and not the sort of race where you want to be running a rookie.
6. 
New Hampshire (Open) — Polling suggests that Kelly Ayotte is the very slight favorite, reversing the dynamic we observed before she entered the race. A libertarianish GOP message ought to play fairly well in this state. I’ve grown cautiously pessimsitic for Paul Hodes.
7. Kentucky (R-Open)
8. 
Arkansas (D-Lincoln) — Polls are all over the place, but Arkansas has turned red in a hurry and Lincoln may be on the verge of triangulating herself out of office with her waffling positions on health care and other issues.
9. Illinois (D-Burris) — Continue to think Mark Kirk is slightly overrated. Even if it’s a fairly bad cycle for Democrats, not sure it will be bad enough for them to start losing open-seat races in the President’s home state.
10. North Carolina (R-Burr) — SOS Elaine Marshall has entered the race and trails Richard Burr, but Burr’s numbers are well below 50 percent.
11. 
Delaware (D-Open) — Beginning to get a little late for Mike Castle to enter. Although Beau Biden would be an underdog against him, he’ll be no pushover and a half-hearted effort might not do it.
12. 
Pennsylvania (D-Specter) — New Quinnipiac numbers should be coming out tomorrow. For the time being, demoting this because of a Franklin & Marsrhall poll that put Specter 8 points ahead (although with high undecideds). Clearly Specter is vulnerable, but I will need to see more consistent polling evidence before I’m persuaded that Pat Toomey is mainstream enough to capture 50%+1 of the vote. With that said, you can make the case that Specter comes up short relative to Joe Sestak on electability dimensions.
13. Texas (R-Open?)
14. Louisiana (R-Vitter)
15. 
Iowa (R-Grassley) — His numbers are falling in a hurry — probably not enough to make him truly vulnerable — but we might have said similar things about Blanche Lincoln or Chris Dodd a couple of months ago. Worth a recruitment effort on behalf of Democrats, especially considering the slight possibility he might get fed up and retire.
16. North Dakota (D-Dorgan) — Not ready to demote this yet, but Hoeven’s purported interest is again starting to look like more of a bluff, and Dorgan has not put himself in the spotlight on health care in the same way that Kent Conrad has.
17. Florida (R-Open)
18. New York (D-Gillibrand) — Variations on theme: Pataki and Giuliani are running out of time to make their decisions, particularly in a state where you’re liable to need $20-$30 million to run a viable campaign.
19. Georgia (R-Isakson)
20. Hawaii (D-Inoyue)
21. Wisconsin (D-Feingold)
22. 
California (D-Boxer) — Rasmussen polled this race again, showing a 9-point lead for Boxer; their July numbers that had her just four points ahead of Carly Fiorina now look like more of a fluke. The main question is whether Fiorina decides to self-finance and creates a money suck for Democrats. I’m on the record as not being that impressed by Firoina as a political entity. I also want to go on the record as being unimpressed by the customer service at Hewlett-Packard, her former company, but we’ll save that complaint for a tweet or something.
23. 
Arizona (R-McCain) — Finally some polling numbers out; PPP shows McCain with somewhat tepid approval numbers, but doesn’t show any of the potential Democratic candidates coming particularly close — certainly not close enough to get anyone like Gabby Giffords interested in a kamikaze mission. Still, McCain has been very quiet, and it might be wise to hedge some against the possibility of a last-minute retirement.
24. 
Massachusetts (D-Open) — Don’t really see this one happening for Republicans, but it’s too early to write off their prospects completely.
25. 
South Carolina (R-DeMint) — State Sen. Brad Hutto, considered a moderately viable opponent, has decided against challenging DeMint.
26. Oklahoma (R-Coburn)
27. Alaska (R-Murkowski)
28. Kansas (R-Open)
29. Maryland (D-Mikulski)
30. Washington (D-Murray)
31. Alabama (R-Shelby)
32. South Dakota (R-Thune)
33. Indiana (D-Bayh)
34. Vermont (D-Leahy)
35. Oregon (D-Wyden)
36. Utah (R-Bennett)
37. New York (Sr.) (D-Schumer)
38. Idaho (R-Crapo)
DELISTED — Nevada (R-Ensign). Almost certainly, he’s going to be near the top of the charts in 2012, but the scandal seems to have blown over enough that it’s not worth worrying about this race for 2010 purposes unless some further, Andrew Brietbart-esque news breaks.