The problem for Democrats is very simple. They expect to win and so are in the process of moving as far left as possible in order to claim a mandate. They will, should they win in November, really not have any mandate for any agenda other than being “not Trump.” But they want to claim it.
That far left drift is a problem. Black and hispanic voters currently have no other party to go to, but there is ample evidence they are starting to grow concerned by the radical secularism invading the Democratic Party that makes it increasingly hostile to religion. Blue collar white voters, likewise, are less and less enamored with the Democrats.