Only Congress Could Change Date of November Election

WASHINGTON—The increasingly strict public-health measures designed to slow the spread of coronavirus are raising concerns about the feasibility of holding the remaining Democratic presidential primary contests, as well as the logistics of holding a November general election if the pandemic is still under way.

The nation’s election system is a complicated thicket of state and federal laws. The process of selecting a presidential nominee is further complicated by the fact that political parties are private organizations and…