In Illinois, Mark Kirk will face voters in a state that Obama won by 17 points. Ron Johnson in Wisconsin will be running in a state where Obama prevailed by 7 points. Both Kelly Ayotte in New Hampshire and Chuck Grassley in Iowa will have races in states that Obama won by 6 points. Pat Toomey in Pennsylvania will be running in a state Obama won by 5 points. Ohio’s Rob Portman will be up in a state Obama won by 3 points. Marco Rubio is up in Florida, which Obama won by 1 point.

While not all of those senators will necessarily seek reelection—Grassley, for example, will turn 83 in 2016—these aren’t great states for Republicans in general, and in a presidential election year there will probably be a larger and more Democratic voter turnout. That is very unlike what we expect to see this year, when a smaller, older, whiter, more conservative, and Republican-leaning midterm electorate will likely put a thumb on the scale for the GOP.

While I was doing a dog-and-pony show the other day with my good friend and competitor Stuart Rothenberg, he made the excellent point that if Republicans do pick up a Senate majority this year, their governing challenge will be keeping some of their fellow Republicans in line—those who know they will eventually be facing voters who don’t always fall in lockstep behind all of the goals and aspirations of the GOP. As a result, the Republican agenda, should the party win a majority this year, might not be as aggressively conservative as some in the party would hope.