2016 is getting more interesting by the minute. This scare ad targets Michael Bennet of Colorado for supporting the Iran Deal. A conservative group is behind it. The production values really fall off in this ad near the end; it looks like a house fire to me.
Bennet won his seat in 2010 by just two points, 48-46. Obama won by a tidy margin in 2012, 51-46.
At that link, a Democratic leader in Colorado calls ad deeply offensive and fear mongering.