Democratic voters in Delaware heading to the polls on Thursday will face a choice that has become increasingly familiar this primary season: casting a vote for a long-secure incumbent, or opting for a surging challenge from the left.
On environmental issues, that decision could be especially fraught, with both of the state’s Senate candidates offering competing green visions for the future.
Sen. Tom Carper, a former governor, has held his seat since 2001 and typically s...