Interstate war is defined by declared belligerency, not violent form.

Evidence

Interstate war, for example, qualifies as such not by the forms of violence in which the parties engage, but by the fact that two independent governments declare a mutual state of belligerency. In the course of their belligerency, the parties ordinarily carry on a wide variety of violent interactions, some of them high on coordination and salience, others at the opposite extreme. — Charles Tilly, Regimes and Repertoires, 732

Categorization

• DEFINE: A definitional point convenient for testing the reader’s asymmetry: what counts as ‘war’ (and potentially what counts as ‘politicization’) is an actor-declared status, not an intrinsic form.
• corroborated: 3 independent passages support this claim — Charles Tilly, Regimes and Repertoires, 732