As I noted the other day, in 2012 and 2008, the GOP presidential nominee did about 7 to 8 points worse, on average, than incumbent Republican senators. So I thought it might be helpful to compare the margins between Trump and some closely watched Senate races featuring incumbents (results are still coming in, so these might shift a little):
Arizona
McCain +11.9
Trump +4
Difference: McCain +7.9
Florida
Rubio +7.7
Trump +1.3
Difference: Rubio +6.4
Illinois
Kirk -14.2
Trump -16
Difference: Kirk +1.8
Missouri
Blunt +3.2
Trump +19.1
Difference: Trump +15.9
New Hampshire (still undecided)
Ayotte -0.1
Trump -0.2
Difference: Ayotte +0.1
North Carolina
Burr +5.8
Trump +3.8
Difference: Burr +2
Ohio
Portman +21.3
Trump +8.6
Difference: Portman +12.7
Pennsylvania
Toomey +1.7
Trump +1.2
Difference: Toomey +0.5
Wisconsin
Johnson +3.4
Trump +1
Difference: Johnson +2.4
A couple things jump out: It seems as though, in many swing states, Trump did not do substantially worse than many Republican incumbents. Portman was the only candidate in these close states who did appreciably better than the +7-8 incumbent advantage of 2008 and 2012.
It also seems as though creating a radical distance from Trump might not have delivered that many votes for Kelly Ayotte and Mark Kirk (Portman also distanced himself from Trump). In New Hampshire, both Maggie Hassan and Senator Ayotte received more votes than Donald Trump and Hillary Clinton, but Ayotte's margin is only a tenth of a point better than Trump's. The New Hampshire Senate race is very close, so those few votes might matter (currently Hassan is up by about a few hundred votes). But there's also a chance that a more unified GOP in New Hampshire could have pulled both Trump and Ayotte across the finish line in the Granite State.
