Congressional Democratic candidates would have to massively outperform Biden and run significantly ahead of his vote share in order to capture the 26 House delegations necessary to settle a contested election in his favour. I'm not sure it's too realistic to expect such a high rate of split-ticket voting in a presidential election year these days.
Polling agencies keep updating their weighting method every cycle.
On the whole, they really don't make as many changes under the hood as you probably think.
I think denying Trump 26 should be their main goal. The GOP has 26 now, and are expected to get NC, so D’s need to beat Schweikert, Ciscomani, and Zinke to do this, and the last one in particular will be extremely tough. Other than that, they need to flip two seats in Iowa, and it’s difficult to see any R go down there other than maybe Nunn; or beat both Van Orden and Steil in WI.
Also they can’t lose Peltola, or Wild/Cartwright, or either open MI seat.
