I read this in the early '90s. It was a collection of scary stories that I got from the school book fair. I don't remember much, but there was a story in there that took place during the civil war (I think) and there was an illustration of a pair of pants that walked around by themselves at night. Something else about a President's ghost, but I could be totally wrong about that.
The most famous story for children about a pair of pants that walked around by themselves is What Was I Scared Of? by Theodore Seuss "Dr. Seuss" Geisel. This story appears in the book "The Sneetches and Other Stories" (Random House, 1961).
However, none of the four stories in this volume is about any armed conflict, or features the ghost of a president. Perhaps the story was anthologized elsewhere.
Dr. Seuss did write a story about the cold war, called "The Butter Battle Book". Seuss's style is so distinctive and compelling that if you read "Butter Battle" at about the same time as "The Sneetches" you could easily misremember which stories appeared in which volume.