The application of a popular front strategy isn’t reducible to simply a commitment to beat Trump. That’s a good start, but not enough. It also entails a readiness to build an extensive set of political and social alliances that while not precluding struggle within the front/coalition, accents broad people’s unity against Trump in the first place. And certainly not a war against the “Democratic Party establishment” (reminds me of the “sixties”).
I can hear a Bernie supporter saying, “But they attack us.” I have no doubt about that, but the left, again because of the existential stakes of this election, should act like the grown up in the room. So far neither Bernie nor many of his supporters have conducted themselves in that manner. It’s not to late. Much hangs on it, including the success of Bernie’s campaign for the Democratic Party nomination.