Legal Definitions - divisum imperium

Divisum Imperium

Divisum imperium describes a legal situation where two different authorities or jurisdictions have power over the same subject matter or geographical area, but their authority applies at different times or under specific, alternating conditions. It is not about two authorities having concurrent power simultaneously, but rather a shifting of primary authority depending on a particular state or event.

• Example 1: Environmental Regulation of a Seasonal Riverbed

  Consider a river that flows through a state park. During periods of normal rainfall, the river is full, and the state park authority has primary jurisdiction over boating, fishing, and environmental protection within the river's banks. However, during a severe drought, the riverbed might dry up completely, exposing significant portions of land. In such a scenario, a federal agency, such as the U.S. Army Corps of Engineers, might temporarily assume primary jurisdiction over the exposed riverbed to manage water resources, protect endangered species habitat, or conduct geological surveys, superseding the state park's authority for those specific aspects.

  This illustrates divisum imperium because the jurisdiction over the *same geographical area* (the riverbed) *alternates* between the state park authority (when the river is flowing) and the federal agency (when the riverbed is exposed due to drought), based on the environmental condition of the water level.

• Example 2: Public Safety During a Major Event

  Imagine a large convention center located within a city. Under normal circumstances, the city's police department holds primary jurisdiction for law enforcement, traffic control, and public safety around the center. However, if the convention center hosts a major international summit attended by heads of state, federal agencies like the Secret Service or the Department of Homeland Security might assume primary jurisdiction over security operations within and immediately surrounding the venue for the duration of the event, temporarily directing local police to a supporting role.

  This demonstrates divisum imperium because the jurisdiction over the *same physical location* (the convention center and its immediate vicinity) *alternates* between local city police (under normal conditions) and federal security agencies (during a high-profile international event), triggered by the nature and scale of the event.