Democratic retirements create fresh challenge for hopes of winning back the Senate

New Hampshire Democratic Sen. Jeanne Shaheen’s decision to not seek reelection marks the latest bit of tough luck for Senate Democrats, who face an increasingly challenging midterm election map as they fight to climb out of the minority.

​ New Hampshire Democratic Sen. Jeanne Shaheen’s decision to not seek reelection marks the latest bit of tough luck for Senate Democrats, who face an increasingly challenging midterm election map as they fight to climb out of the minority. Read More Breaking News, Latest News and Videos | CNN