I'm not sure how assumed that is. From Wikipeda:

According to Stephen J. Lukasik, who was deputy director (1967–1970) and Director of DARPA (1970–1975):

The goal was to exploit new computer technologies to meet the needs of military command and control against nuclear threats, achieve survivable control of US nuclear forces, and improve military tactical and management decision making.

I note in practice it mostly still works in war zones unless one of the countries makes a major effort to block its own citizens from access.