Many GOP voters do not like Yoder, he is too liberal for their taste. Their support for Yoder has been very lukewarm and many seem likely to skip the election. On the other hand, this is the most liberal district in Kansas and these GOP voters do not like the Governor candidate, Chris Kobach. They will vote for the Democrat or the Independent. These voters may vote for Davids.
This will be a perfect storm for the Democrats and Kansas might elect an avowed Socialist to the Congress.
Once again the only thing saving a Bush League Republican is that the Democrat is worse.