Though more Republican-held seats are up for grabs in November, Democratic struggles mean the GOP has improved its likelihood to take control of the Senate. Here are the key contests to watch.
The top 10 Senate races that are most likely to flip to the other party wglt.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from wglt.org Daily Mail and Mail on Sunday newspapers.