Apparently because Dennis ran for President Annenberg's FactCheck dot org takes on Joe Cimperman's claims against him in the Congressional primary. I'm not convinced by their argument about Dennis's relative effectiveness, but the fisking on FactCheck is a better place to start than comparing the campaign lit from either side.
Not that it matters. As a veteran observer recently told me, 40% of the Democrats in his district would vote for Dennis's corpse.
Uphilling it, and an AWP 2014 retrospective
17 hours ago