What did Mark Udall and John Hickenlooper do wrong?

[solarstorm]

At the beginning of this year I considered Colorado safe Democrat, both in the senatorial and in the gubernatorial election. As recently as two months ago, I couldn't have imagined that both Democrats would struggle in a state that has become more and more Democrat-leaning.

Udall was even leading until September, albeit only by small numbers. But suddenly the tide began to turn, and he cannot keep pace with Cory Gardner anymore.
Hickenlooper's poll numbers aren't as bad as Udall's, but I'm still shocked that the gubernatorial race is a tie, when I'd been assuming a walkover for him...

What went wrong? Are the two of them just members of the wrong party, or do their struggles have a specific background?