“The public can expect little disruption in their day-to-day activities since much of the exercise will be conducted in remote areas,” the organizer of the exercise, the Army Special Operations Command at Fort Bragg, N.C., said in a statement Monday.

But in a larger sense, Jade Helm 15 has already caused disruptions, particularly in Texas.

On the orders of Gov. Greg Abbott, the Texas State Guard will monitor Jade Helm 15 from Camp Mabry in Austin, the state capital. So will at least one national group of unofficial monitors and protesters that calls itself Counter Jade Helm. It plans to have teams of volunteers follow Army vehicles and post their locations on its website.

Dr. Campbell and others said much of the paranoia over Jade Helm 15 was the outgrowth of the anti-Obama sentiment that is widespread in Texas. Residents supported the governor’s decision to have the state monitor the military’s activities. “I think there’s an overall distrust of the government now,” Dr. Campbell said. “If we had a government that we felt had our backs, I don’t think anybody would give it the time of day.”

Training exercises off base involving role-playing are not new. But the size and scope of Jade Helm 15 make it unusual.

Image People at Hidalgo’s, one of the few restaurants in the town of 500. Credit... Tamir Kalifa for The New York Times

The military exercise will train Special Operations troops in what Army planners call “unconventional warfare.” The exercise is being conducted in rural Texas because the military needed “large areas of undeveloped land with low population densities with access to towns,” and wanted soldiers to adapt to unfamiliar terrain as well as social and economic conditions, according to Army documents.