Liam Donovan
Not mutually exclusive, but IMO the core insight of 2014 that was absent in 10/12 (and rapidly eclipsed by Trump) was the value of rallying behind candidates who could do both and avoiding the establishment/grassroots binary. Schumer failing at this in sundry ways.
David Weigel
Wrote about how the Dem center/establishment is trying, but not really succeeding so far, of using the Platner mess to reassert control of primaries. One Q I had: Why is what McConnell did in 2014, using SLF (and the Chamber of Commerce), to swat down ideological candidates, so much harder for Schumer/Jeffries? One answer, from Josh Holmes, the Luca Brasi of that strategy https://www.semafor.com/article/07/15/2026/how-obama-fits-into-democratic-centrists-comeback-plot