It's important to note that Beauprez and Gardner were roughly equal in terms of candidate quality. Why did Beauprez lose then? Because Hickenlooper campaigned on multiple issues.
Hickenlooper got credit for an economic recovery in the state.
http://research.stlouisfed.org/fred2/series/CONAHad it not been for the GOP wave and gun control he would of gotten 10% instead of a 3% margin. He actually increased his votes compared to 2010, by almost 100k votes.
Also he apologized on gun control and even sang with the banjo(ŕ-vis bill clinton playing the sax in 1992) to try to lure rural coloradans back or at least make them less angry at him and it worked.
https://www.youtube.com/watch?v=KeT86_e89yUhttps://www.youtube.com/watch?v=mT5lGkh96IEAlso i bet just having the last name Hickenlooper, helped despite the headwinds against him.
Delays in Keystone and Immigration reform wasn't a smart move by Obama, in states like AK, CO and NC, states in which we should of won. The public deserved to know where the Democrats stood on these issues, and yes Torture could of turned these races in the Democratic favor along with putting them on record with the other two issues.
If Obama approved Keystone then the races in those three states would of been leaning more democrat, however amnesty i doubt it. If Obama announced amnesty before the election the democrats would of been even more trounced.