Dan Pfeiffer: “Chuck Schumer did Mills no favors by endorsing her so publicly.”“Schumer is particularly unpopular with the party base and has taken the brunt of the frustration with the Democratic Party’s pushback against Trump. In a recent CNN poll, Schumer had a net negative favorability rating among Democrats — the only one of the four congressional leaders underwater with his own party.”“But this is about more than just Schumer.”“Democratic voters are furious at the leadership and skeptical of the Democratic establishment. In primary after primary this cycle, there is a penalty for being the choice of Democratic leadership.”