By Charlie Cook
No matter how entertaining the circus of the presidential campaign, also remember this: Control of the Senate is definitely in play. Maggie Hassan offered a reminder Monday when the Democratic governor of New Hampshire announced that she will challenge Sen. Kelly Ayotte, a first-term Republican, in next year’s elections. Hassan had been silent about her intentions, but public polling suggests that the race would be very close; most surveys show the Republican incumbent with the narrowest of leads.
Republicans hold a 54-to-46 advantage in the Senate. This means that Democrats would need a net gain of four seats if they hold onto the White House, or five seats if they don’t (because the vice president can break a Senate tie).
The GOP’s majority is flimsy, though. Republicans have 24 seats at risk next year, compared to just 10 for the Democrats, and seven are in states that President Obama carried in 2012. One of those seven seats looks safe; Iowa’s six-term incumbent Chuck Grassley is widely seen as both unbeatable and unlikely to retire. But the other six are in real danger—incumbents Ayotte, Mark Kirk (Illinois), Ron Johnson (Wisconsin), Pat Toomey (Pennsylvania), and Rob Portman (Ohio), plus a seat in Florida held by Marco Rubio, who is running for president rather than Senate reelection.
The result: Democrats have fared well in Senate races when the presidency was up for grabs. In 2008 and 2012, they picked up eight and two seats, respectively. Their gain in 2012 wasn’t larger because they’d already picked up four seats in 2000 and six more in 2006—the two previous times this class of senators had faced voters—leaving fewer additional seats within their reach.
Conversely, Republicans did wonderfully in the midterm elections of 2010 and 2014, when they picked up six and nine seats, respectively.
I’m not a believer in coattails—the notion is highly simplistic. But the dynamics of voter turnout, the issue agenda, and unpredictable events that tip a close state one way in a presidential race can just as easily tip that state’s close Senate race in the same direction. (my emphasis)
READ all of Charlie Cook’s comments from the National Journal here .