A rough sketch of a Senate projection

I’m in the mood to see how the Senate race nationwide looks right now, but I don’t want to rely on RCP or Cook or someone else. I’m going to do it myself. Take it for what it’s worth.

Situation

Senate right now: 58 D-41 R, with the WV vacancy likely to be filled by a Democrat to make it 59 D-41 R.

Seats up right now: 18 D-18 R.

Seats therefore not up: 41 D-23 R.

Minimum result needed for majority: -9 for Democrats, +10 for Republicans.

Method

I’m going to work off the polls when they’re available, and make guesses otherwise. That’s usually easy because the seats that aren’t polled are typically safe.

Seats

AL: Richard Shelby: Primaries done. No polling I know of. 99.9% R victory.

AK: Lisa Murkowski: Primaries in progress. Only polling I can find is of a hypothetical Murkowski v Sarah Palin primary. 99.9% R victory.

AZ: John McCain: Primaries in progress. JD Hayworth well behind in primary. McCain up 57-28 (MoE 4.5) in last poll. 99% R victory.

AR: Blanche Lincoln: Primaries done. John Boozman up 61-32 (MoE 4.5) in last poll. 99% R victory.

CA: Barbara Boxer: Primaries done. Boxer up 45-41 (MoE 4) and 48-43 (MoE 4.5) in latest polls. 30% R victory.

CO: Michael Bennet: Primaries in progress. Republicans Jane Norton and Ken Buck both with small leads in recent polling. 67% R victory.

CT: Chris Dodd (retiring): Primaries in progress. Richard Blumenthal well ahead in polling. 1% R victory.

DE: Joe Biden (resigned): Primaries in progress. Mike Castle well ahead in polling. 99% R victory.

FL: Mel Martinez (resigned): Primaries in progress. Polling mixed. 30% R victory.

GA: Johnny Isakson: Primaries done. No polling I can see. 99.9% R victory.

HI: Daniel Inouye: Primaries in progress. No polling I can see. 0.1% R victory.

ID: Mike Crapo: Primaries done. One poll last month with Crapo up 44. 99.9% R victory.

IL: Barack Obama (resigned): Primaries done. Polling close with Mark Kirk slightly up. 60% R victory.

IN: Evan Bayh (retiring): Primaries done. Dan Coats leading. 95% R victory.

IA: Chuck Grassley: Primaries done. Grassley leading well. 95% R victory.

KS: Sam Brownback (retiring): Primaries in progress. Republican Jerry Moran leading all polls. 99.9% R victory.

KY: Jim Bunning (retiring). Primaries done. Randal Paul with stable lead. 70% R victory.

LA: David Vitter: Primaries done. Vitter well ahead in most polls, but down to 9% lead in one poll. 90% R victory.

MD: Barbara Mikulski: Primaries in progress. No polls I can find. 0.1% R victory.

MO: Kit Bond (retiring): Primaries in progress. Roy Blunt has lead all year in the polls, though not by a lot. 70% R victory.

NV: Harry Reid: Primaries done. Sharron Angle has led all year, except for one poll which had her suddenly below 40, where before and since her minimum has been 44. Reid has never been over 43. 70% R victory.

NC: Richard Burr: Primaries are done. Burr has led the whole way but his lead has been volatile. 70% R victory.

ND: Byron Dorgan (retiring): Primaries are done. John Hoeven leads by so much he breaks the graphics in my analysis tool. 99.9% R victory.

NH: Judd Gregg (retiring): Primaries in progress. Kelly Ayotte still has led the whole way, but opponent Bill Binnie has surged. 90% R victory.

NY: Chuck Schumer: Primaries in progress. Is this race even contested? A hypothetical poll against Larry Kudlow has Schumer up 45. 0.1% R victory.

NY: Kirsten Gillibrand: Primaries in progress. Gillibrand leads every matchup. 1% R victory.

OH: George Voinovich (retiring): Primaries done. Polls very close with Lee Fisher taking a slight edge. 45% R victory.

OK: Tom Coburn: Primaries done. No polling I can find. 99.9% R victory.

OR: Ron Wyden: Primaries done. Wyden comfortably ahead. 10% R victory.

PA: Arlen Specter (primaried): Primaries done (especially for Specter). Polls close and volatile with Pat Toomey taking a small edge. 65% R victory.

SC: Jim DeMint: Primaries done. Democrats trying to take down their own nominee, they’re so concerned. 99.9% R victory.

SD: John Thune: Primaries done. Unopposed. 100% R victory.

UT: Bob Bennett (primaried): Primaries done. No polls I can find, but Mike Lee is the heavy favorite. 99.9% R victory.

VT: Patrick Leahy: Primaries in progress. No polls I can find. 0.1% R victory.

WA: Patty Murray: Top Two Primary in progress. Murray led for a long time but tied the last poll. 40% R victory.

WI: Russ Feingold: Primaries in progress. Feingold leads but by much less than expected. 40% R victory.

The simulation

100,000 trials using the probabilities above.

Results

A 5 seat Republican gain is most likely according to these estimates, with 6 seats coming in slightly behind. Those two outcomes account for 43% (43214/100000) of the curve. Only 70/100000 trials gave Republicans a Senate majority. 48/100000 gave Democrats a gain.

I’m actually surprised. I didn’t think using the polls would come up with a result so close to what I expect. I suppose I’m influenced by the polls!