In The Stand the United States Military is portrayed as being the main culprit behind the creation of Captain Trips. As well as being ultimately responsible for the destruction of modern civilization when the virus escapes from Project Blue. The military is responsible for the quarantine efforts afterwards. In particular the U.S. Army is shown having a very heavy hand with little to no qualms about killing Americans in vast numbers in an effort to keep the pandemic contained and the news about Captain Trips under wraps.
The Mist: Novella
The U.S. Army makes an appearance in "The Mist", in the form of a handful of soldiers who are stationed at the unnamed military base near Bridgton, Maine. That base houses the Arrowhead Project, a mysterious government and/or military program that no one from the base has ever shared any information on with locals. Nonetheless, word gets out in a small town, and people in Bridgton speculate about the Arrowhead Project and what it involves. Theories include "messing around" with "different" atoms, and attempting to open a portal into another dimension.
Sometime during or after a massive lightning storm that hit the Bridgton area during a scorching hot summer, the base was overrun by the mist, and none of its personnel were ever seen or heard from again. The only exception to this were the two soldiers who were caught in the Federal Market at the time the mist enveloped it. They kept a low profile at first, avoiding all contact with the civilians, then hanged themselves together in the store's stock room. David Drayton and Ollie Weeks, the latter a Vietnam War veteran, debated how much the "Army kids" knew, and why they hanged themselves, but came to no decisive conclusions.
It is unknown whether the United States Military overall succeeded or failed in responding to the mist as it continued to spread.