There is one single lesson for Democrats to learn from the KS-04 race tonight: Contend for every district, no matter how hopeless it feels.
Yes, Republican Ron Estes won, but he won by less than six points. This, in a district that is heavily Republican in a state where even Republicans loathe their governor and aren't that enamored of Trump right now either.
This district was won by 31 points last November. Less than six months later, the Republican candidate had to be shored up with Trump/Pence robocalls and a special visit from Ted Cruz to save him from an even more humiliating margin than 5+ points.
Yeah, it's a drag that Thompson didn't win. There are a lot of factors in play, not the least of which is heavy voter suppression in Kansas and ads painting James Thompson as a baby-killing, gay loving Democratic demon.
Should the DCCC have put money into the district sooner? I really think the stealth nature of Thompson's candidacy helped him. On the other hand, when the Republicans started pulling out the stops, it might have been helpful to have some money in there.
Either way, do not minimize the message sent in Kansas tonight. A Democrat came within 6 points of winning in Charlie Koch's back yard. That is an accomplishment for which Thompson and all the grassroots groups supporting him should be patting themselves on the back.