The outcome of six races could determine whether the U.S. remains in Democrats ' hands . Julian Zelizer : Democrats citing GOP extremism ; Republicans cite Obama 's policies . In four of the races , Democratic incumbents are seeking to win re - election . Zelizer : Can White House reverse historical pattern of midterm losses ?
The outcome of six races could determine whether the U.S. remains in Democrats ' hands . Julian Zelizer : Democrats citing GOP extremism ; Republicans cite Obama 's performance . In four of the states , Democratic incumbents are seeking to win re-election . Zelizer : Can White House reverse historical pattern of midterm losses ?