It is either public or private. It is not intended here to speak of the latter.
Public war is either civil or national.
Civil war is that which is waged between two parties, citizens or members of the same state or nation. War is not only an act, but a state or condition, for nations are said to be at war not only when their armies are engaged, so as to be in the very act of contention, but also when, they have any matter of controversy or dispute subsisting between them which they are determined to decide by the use of force, and have declared publicly, or by their acts, their determination so to decide it. National wars are said to be offensive or defensive. If a nation sees itself menaced with an attack, its first act of violence to prevent such attack, will be considered as defensive. To legalize a war it must be declared by that branch of the government entrusted by the Constitution with this power.