a dirty word.
Gomez is a liberal on the issues:
https://jimmygomezforcongress.com/issues/
As to politico framing this as a "setback for the "Sanders wing", is not so subtly trying to put a wedge between Democrats.
For instance, sexism charges were leveled at Carmona which had nothing to do with being part of the "Sanders wing" or part of the "establishment", but could have been a factor:
http://www.rawstory.com/2017/04/what-would-bernie-do-ex-sanders-staffers-smack-former-top-deputy-with-sexism-claims/
Probably the biggest part that had NOTHING to do with being part of the "Sanders wing" or part of the "establishment" wing as characterized by Politico, was the fact that 24 people were running in that special election.
I think the characterization of the Politico article as a contest between the "establishment" and the "Sanders Wing", is purely meant to stir things up and attract readers, rather than reflect the political reality, at least as far as this special election is concerned