Why didn't Jason Kander run for governor instead?

[The Arizonan]

I think Jason Kander has a better chance of winning the governor's race than trying to defeat Roy Blunt since gubernatorial elections are much less partisan than senate elections and Jay Nixon is term-limited. Missouri elected and reelected Jay Nixon, a Democrat, while it voted against Obama in 2008 even though he had everything going for him.

I have a feeling that Kander will lose against Blunt even with Hillary Clinton on top of the ballot and Blunt probably having some negatives since this is Missouri after all.

[Ebsy]

Because Koster is running for governor and the Missouri Democratic Party has only survived thus far through party unity. We really don't have the luxury of fighting among ourselves when so much is at stake.

[bballrox4717]

Kander is also only 34 years old, so if he runs against Blunt and loses in a competitive race, it won't completely destroy his political career, and helps him develop statewide recognition.

[henster]

He would lose to Koster who would raise far more $$ than him and has a far more impressive electoral record.

[Amenhotep Bakari-Sellers]

A poll showed that Blunt was vulnerable; and it proved not to be the case.

[IceSpear]

As others have said, the incumbent Democratic AG is already running for governor.