That is a good question. After thinking about it for a bit and going back through the story, I do not believe that the story has a single protagonist. I believe that "The Machine That Won the War" has three protagonists. They are Lamar Swift, Max Jablonski, and John Henderson. The three men get just about equal page time and speaking parts, and the story focuses on the three men talking about their involvement in the war effort against the Denebians. As they discuss Multivac, and its problems, the men discover that all three of them were more involved in winning the war than they initially thought. All three men didn't fully trust Multivac, so each man manipulated either the input, output, or final decision of Multivac by his own intuition. Consequently, the reader realizes that a machine didn't win the war. The decisions made by all three of these men together won the war. Because each man is equally important to the final outcome, I feel that each character deserves the label of protagonist.