What does the term "insurrection" refer to in terms of military action?

The term "insurrection" specifically refers to an armed uprising against an established authority, typically within a country. In the context of military action, insurrection involves a rebellion by a group of people against the governing power, seeking to overthrow or challenge its control. This definition is critical in understanding the dynamics of internal conflict, as it highlights the use of force and organized resistance against established governmental structures.

In contrast, the other options describe scenarios that do not align with the definition of insurrection. For instance, a peaceful protest against government policies does not involve armed conflict and therefore does not constitute an insurrection. A formal declaration of war implies a different legal and political context, usually between recognized nation-states rather than internal factions. Lastly, a military campaign conducted for foreign aid does not pertain to internal rebellion or uprising against authority, as it focuses on external assistance rather than challenging an establishment.