Historically, rebel groups seeking to overthrow a recognized government or to secede from a State have sought “belligerent status”—a legal standing akin to that accorded a government and bringing the law of international armed conflict into play for both sides.
A rebel group gained “belligerent status” when all of the following had occurred: it controlled territory in the State against which it was rebelling; it declared independence, if its goal was secession; it had well-organized armed forces; it began hostilities against the government; and, importantly, the government recognized it as a belligerent.

In more recent times, however, governments have simply refused to grant recognition to groups rebelling against them. Governments are loath to admit that they have lost effective control of territory, and are reluctant to grant legal standing to rebel groups.

This refusal has serious legal and humanitarian consequences. Where insurgents did not have belligerent status, a government would not be bound to treat insurgents according to the law of international armed conflict, thus often paving the way for savage and inhumane incidents.

As a countermeasure, the international community has arranged for certain minimum standards of humanitarian law to be triggered by facts on the ground without waiting for governments to recognize belligerents or a state of belligerency. A confrontation is deemed to be an internal (or in technical terms, “non-international”) armed conflict when the fighting is intense, organized, and protracted enough to go beyond temporary disturbances and tensions. Necessarily, an internal armed conflict is confined within a State’s borders and generally does not involve foreign States as parties. As soon as the situation on the ground meets these criteria, parties are expected to conform to a distinct body of humanitarian law crystallized most notably in Common Article 3 of the Geneva Conventions of 1949. If the rebel group has effective control over some part of national territory, the provisions of Additional Protocol II may also apply. In either case, the legal standing of the parties is unchanged.

In effect, humanitarian law sidesteps entirely the sensitive issue of recognition.

(See international vs. internal armed conflict.)