Any caucus that can take and then hold together under a group of guiding principles about 30 House seats now in he hands of republicans will control the ability to swing the House of Representatives toward or away from legislative projects on the Democratic agenda Similarly any group that can take and hold 10-ish formerly republican Senate seats will control the ability to swing the Senate.

Considering the national level of populist discontent on the right and left. The possibility of a determined caucus moving significantly toward that following the 2018 midterms isn't impossible, and unlike a presidential competitions it doesn't risk everything in a single race.