With Jim Martin's loss in Georgia, we now know that the Democrats will not achieve a 60-seat senatorial caucus once the 111th Congress convenes next month. In practice, however, the line between 59 (or 58) votes and 60 was never so bright as it seemed. Moderate Republicans are an endangered species these days, but there are still a few of them left, as well as several other quasi-moderates who either get along with Obama or are under some form of electoral pressure in their home states. Conversely, there are more than a couple of Democrats in the chamber whose votes Obama can't take for granted.
In practice, there will be a group of four or five senators in each party who line up just to either side of the 60-seat threshold and will find that they're suddenly very much in demand. If Obama's approval ratings are strong, he should have little trouble whipping the couple of Republican votes he needs into shape, and should clear 60 comfortably on key issues. But, if Obama proves to be unpopular, there remain enough conservative, red-state Democratic senators to deny him a simple majority on key issues, much less 60 votes.
Let's start with the Republicans, ranking the senators based on their likelihood of crossing party lines to vote with Obama. We'll begin counting upward from the number 59, which assumes that Norm Coleman will win the recount in Minnesota, and that the first Republican vote that Obama gets is his 59th overall. If Al Franken wins instead, add one to each of the numbers below.
This ordering is based on a combination of objective and subjective considerations, and should be considered rough -- among other things, it will diverge based on the particular issue at hand.
59. Snowe (ME). Obama won Maine by 18 points, making it the bluest state to be home to a Republican senator -- and in fact, it has two of them. Per Voteview, Olympia Snowe is incrementally more liberal than Susan Collins; she's also up for re-election two years sooner. It will be very interesting to see how the two of them will legislate under an Obama administration.
60. Collins (ME). See above.
61. Specter (PA). Under re-election pressure in a state that Obama carried by double digits. Mitigating factor: possible that he'll be under pressure from the right too in the form of a primary challenge.
62. Lugar (IN). On good terms with Obama, who (barely) won his state. Voteview has him becoming slightly more liberal over the past several Congresses.
63. Voinovich (OH). Under serious re-election pressure. Has often been moderate -- or even slightly left of center -- on pocketbook issues, and increasingly so on other ones.
...the preceding five senators will be under the most pressure to side with a popular Obama, but several others may come into play on occasion:
64. Coleman (MN). If he beats Franken by 50 votes or something, will that chasten him into being more bipartisan? Possibly not, but he's been relatively moderate, and Minnesota remains a solidly blue state.
65. McCain (AZ). Hard to know where his headspace will be for a variety of reasons, particularly as he's legislated all over the spectrum (from authentically moderate to strongly conservative) in different Congresses. Obama may have sent him something of an olive branch by appointing Janet Napolitano, his potential rival in 2010, to head of Homeland Security.
66. Grassley (IA). Up for re-election -- although he'll probably win easily if he doesn't retire. Still, something like an aging Supreme Court justice, Grassley has moderated in recent years, particularly on good government issues. Iowa is turning bluer.
67. Murkowski (AK). Up for re-election in 2010, although it's unclear if she'll face a serious challenge. Pro-choice. At heart, her politics might not be that different than Snowe or Collins, although she faces less electoral pressure to moderate.
68. Gregg (NH). Fairly conservative really, but under significant enough re-election pressure that he may assist Obama outside of his hallmark issue of taxation.
69. Bond (MO). See above, although Bond's bugaboos are in foreign policy rather than fiscal policy.
Others to watch: Hatch (UT), Martinez (FL), Johanns (NE)
It would not surprise me if we see a bit of cross-over between the parties this year -- that is, if a Republican like Olympia Snowe winding up with a more liberal voting record than a Democrat like Mary Landrieu.
For this group, we'll count downward from 58.
58. Landrieu (LA). Always a problem for Democrats on key votes. LA is trending red.
57. Pryor (AR). Is slightly more popular than Landrieu and also slightly more liberal, but the same basic story applies. Arkansas is one of the few states moving in the wrong direction for Democrats, and Pryor never really showed any signs of warmth toward Obama.
56. Nelson (NE). By most statistical methodologies, the most conservative Democrat in the chamber. However, he endorsed Obama early. I think Obama will have fewer near-term problems with the Midwestern blue dogs than the Southern ones.
55. Lincoln (AR). More liberal by some margin than Mark Pryor, but she's up for re-election in 2010, and Obama may have reverse coattails in Arkansas. If Mike Huckabee enters the race against her, look out.
...that group of four senators represent Obama's most significant problems, but he'll have several others that he needs to keep an eye on:
54. Lieberman (CT). Who knows. My hunch is that he'll want to start getting back in Democrats' good graces, but this is a man who likes the spotlight and blockading legislation is a good way to accomplish that. Still, fundamentally he remains fairly liberal outside the sphere of national security.
53. Dorgan (ND). Dorgan endorsed Obama early, but he just ain't all that liberal.
52. Conrad (ND). See above. Perhaps slightly more liberal than Dorgan on issues like energy.
51. Baucus (MT). His proactive health care proposal suggests he may be more comfortable than he once was with progressive policy, but will be a problem on some issues like the environment.
50. Tester (MT). Only endorsed Obama very late in the process, and not as liberal as the netroots think. That Montana nearly went blue may relieve some pressure.
49. Byrd (WV). Warm relations with Obama, but could potentially buck him on cultural issues.
48. Webb (VA). Never really got on the Obama bandwagon and has his idiosyncratic streak.
47. Salazar (CO). One of the few Democrats under re-election pressure, although it's mitigated by the fact that Obama is more popular in Colorado than he is.
Others to Watch: Hagan (NC), Rockefeller (WV), Warner (VA)
The takeaway here is that although political capital is important to any president, it may be particularly so for Obama given the present configuration of the Senate and the fact that he appears to have a fair amount he actually wants to get accomplished.