Why did Bennet win and Udall lose?

[Corbyn is (no longer) the leader of the Labour Party]

One incumbent won and one incumbent lost, but they were both in near identical midterm wave years. Why did Bennet survive while Udall lost?

[JMT]

I believe, in part, it had something to do with their respective general election opponents. Bennet faced a weak opponent in Ken Buck, whereas Udall faced a strong opponent in Cory Gardner.

[Mr. Smith]

Buck was a terrible candidate, whereas Gardner was competent.

Given that Bennet and Udall both ran Z-list campaigns [for 2014, I'm pretty sure Mr. Failey in Iowa did a better job], this is reason enough.

[Roll Roons]

I believe, in part, it had something to do with their respective general election opponents. Bennet faced a weak opponent in Ken Buck, whereas Udall faced a strong opponent in Cory Gardner.

That's exactly it. Buck's gaffes made him look crazy and turned a lot of people off, considering that at one point he compared homosexuality to alcoholism. Gardner's campaign made sure to appeal to moderate swing voters, rather than just the base, and he let Mark Uterus dig his own grave with his abortion obsession.

[💥💥 brandon bro (he/him/his)]

Buck tanked (rightfully so) for being a "buyer's remorse" rape apologist and belittling a female primary opponent for wearing high heels. According to exit polling he lost women by 17 points and white women (!) by 7 points. Despite this Bennet only won by 30K votes.

Udall overcorrected and ran a campaign centered almost entirely about abortion. He lost a lot of ground outside the Denver metro.

[Amenhotep Bakari-Sellers]

Due to fact 2014 was in a 6th yr of a Dem presidential term. The GOP underperformed and only netted 12 House seats and in a typical midterm, they should of netted 20

[Brittain33]

I don’t buy that Udall’s focus on abortion doomed him. For one, it was an accurate argument for him to make since Gardner has supported all of Trump’s judges. Secondly, the partisan tide in 2014 was going to pull down Udall against Gardner no matter what he did. I have no doubt Udall had polling showing this was his best approach.

[Mr.Phips]

Due to fact 2014 was in a 6th yr of a Dem presidential term. The GOP underperformed and only netted 12 House seats and in a typical midterm, they should of netted 20

The fact that Republicans already held 234 seats in 2014 meant there was not many vulnerable Democratic seats left that they could win.  Republicans did very well to net 12 seats given this.

[Corbyn is (no longer) the leader of the Labour Party]

Ok here is a better question maybe, why did Hickenlooper win twice?

[Person Man]

Ok here is a better question maybe, why did Hickenlooper win twice?

Because he was very cautious about everything.

[Skill and Chance]

He ran a nearly single issue cultural left campaign in as an incumbent in an at best average economy.  Enough said.  In retrospect, he should have been a warning sign for Hillary Clinton's campaign.