Using a similar methodology as my model for the U.S. House, I predict that the Republicans will gain six seats in the U.S. Senate. Here is a seat-by-seat summary (margin of victory in parentheses; party turnover in italics):
Safe Democratic, 6 Seats (15 percent+) :
CT (Dodd)
Inouye (HI)
Mikulski (MD)
Schumer (NY-A)
Gillibrand (NY-B)
Leahy (VT)
Strong Democratic, 5 Seats (5.0 -15.0 percent):
Boxer (CA)
IL (Burris)
Reid (NV)
Wyden (OR)
WV (Byrd)
Weak Democratic, 2 Seats (0.0 - 5.0 percent):
Murray (WA)
Feingold (WI)
Weak Republican, 6 Seats (0.0 - 5.0 percent):
Bennet (CO)
DE (Kaufman)
FL (LeMieux)
NH (Gregg)
OH (Voinovich)
PA (Spector)
Strong Republican 3 Seats (5.0 - 15 percent):
Grassley (IA)
MO (Bond)
Burr (NC)
Safe Republican 15 Seats (15.0 percent+):
AK (Murkowski)
Shelby (AL)
McCain (AZ)
Lincoln (AR)
Crapo (ID)
IN (Bayh)
Isakson (GA)
KS (Brownback)
KY (Bunning)
Vitter (LA)
ND (Dorgan)
Coburn (OK)
DeMint (SC)
Thune (SD)
UT (Bennett)