In 2014, Democrats, the majority party in the Senate, had to defend most of the seats up for election, more than a few in unfriendly territory. That year, Republicans took back control of the chamber, picking up nine seats.
Democrats are counting on a similar scenario unfolding to their advantage next year: Republicans currently have a 54-46 advantage, but of the 34 seats up in 2016, only 10 are held by Democrats.
Any outcome depends on unpredictable events over the next 10 months: the presidential race, whether the stronger candidate wins selective primaries, the effectiveness of some challengers, and changing economic or national security issues.
With that critical caveat, Democrats say there’s at least an even chance they will score a net gain of four or five seats. Republicans acknowledge they may lose a couple seats, but believe they will maintain control. This is almost a mirror reflection of the analysis two years ago.