Tom Sullivan has a very thoughtful analysis of the outcome of GA-06.

Tom Sullivan, Hullabaloo: Collective Sigh

This is on target.

But there is also the improving “their electoral infrastructure” part of Marshall’s equation. There is certainly an over-reliance on a priesthood of consultants, data geeks, and technological terrors for solving what are essentially human relations problems. Voters are human beings, not data points or cattle to be herded. It might help if campaigns treated them as such. But if my area is any indication, there is also this. Few county organizations have built up the institutional memory and skills for running effective get-out-the-vote programs year to year, mid-term to presidential to municipal. Activists age out of high-intensity campaign work and take what they’ve learned (if anything) with them. Many smaller counties rely on national coordinated campaigns to parachute in every four years (if they do) to tell them what to do when the ambitious twenty-something staffers don’t know themselves.

Winning an election is not just a contest of ideas; it is a contest of skills. At a meeting recently, one county Democratic officer expressed interest in learning about all these “high-tech” tools we use. I think that meant computers. Democrats need an upgrade from the grassroots up as much as from the top down.

Welcome to the real world after the death of the donkey.  That is, Democrats in most Republican majority areas are fighting against a negative perception of their brand, carefully cultivated over three decades.

That factor seemed to be worth 5%-10% to Republicans in an otherwise close race.  In 2016, it likely made the difference in a lot of states.  The brand itself is a lead weight.  That’s why 2014 and 2016 were existential elections for both parties.  And why Trump is the lead weight for the Republicans (the only sign of hope).