How Michael Bennet Got Lucky
The Democrat was supposed to be the incumbent the GOP knocked off

With a crowded GOP field in disarray, Colorado's Democratic Sen. Michael Bennet is looking more and more like a safe bet for re-election. (Bill Clark/CQ Roll Call)

Colorado Sen. Michael Bennet may turn out to be the luckiest senator of 2016.  

He was supposed to be the only Democratic senator Republicans had a chance of knocking off this year.