What happens if Republicans win the Senate in 2014?

The Washington Post's Monkey Cage gives Republicans an 82 percent chance of taking the Senate. The New York Times' Upshot gives them a 54 percent chance. Nate Silver's FiveThirtyEight is also projecting that Republicans will win the Senate.

Republicans are likely to take the Senate in 2014. The question is: what happens next? Republicans already control the House. And Vox forecasts that Democrats have a 99 percent chance of keeping the White House. So I asked Senate staffers on both sides of the aisle whether Majority Leader Mitch McConnell —...