Democrats have only days to decide between two lackluster options if they want to prevent the “existential threat” a second Trump administration represents, a well-heeled political strategist argued Wednesday. Melissa DeRosa — a state-level campaigner for former President Barack Obama and former staffer of disgraced New York Gov. Andrew Cuomo — delivered a walloping reality check to her political party Wednesday in the form of a Daily Beast editorial. “Knowing the existential threat that a second Trump presidency would present compounds the recklessness and culpability of everyone involved,” a…