Beginning in July, the U.S. Army Special Operations Command plans a series of training exercises with other military units across Arizona and six other states in the Southwest.
The plan, Army officials say, is to develop new warfare tactics and procedures in a landscape not unlike the shifting terrain of combat zones in the Middle East and Afghanistan.
"The diverse terrain in these states replicates areas special operations soldiers regularly find themselves operating in overseas," the Pentagon said in announcing the exercises, dubbed Operation Jade Helm 15 and scheduled to run for eight weeks over the summer.
It didn't take long for other theories to emerge.
"Way worse than you realize," conspiracy-oriented Texas radio host Alex Jones' InfoWars website warned Friday. "Military, police working together toward population control."
Why, several right-wing bloggers wanted to know, does a widely circulated map purporting to be an Army training document for the exercises divide the region into red states and blue states, with red states—Utah and Texas—labeled "hostile," and blue states—California, Nevada, Colorado—labeled "permissive?"
Soon, a Republican congressman from Texas, Louie Gohmert, was wondering the same thing.
"I was rather appalled that the hostile areas amazingly have a Republican majority, 'cling to their guns and religion,' and believe in the sanctity of the United States Constitution," Gohmert said in a statement last week. "When the federal government begins, even in practice, games or exercises, to consider any U.S. city or state in 'hostile' control and trying to retake it, the message becomes extremely calloused and suspicious."
It all came to a head when Texas GOP Gov. Greg Abbott—who presides over a state that is home to 1.7 million military veterans, along with Ft. Hood and Ft Bliss—ordered the commander of the Texas State Guard to monitor the exercises and give him "regular updates" on the "progress and safety of the operation."
"During the training operation, it is important that Texans know their safety, constitutional rights, private property rights and civil liberties will not be infringed," the governor declared.
The unexpected controversy has caused plans for one of the biggest peacetime military exercises in six decades to sweep across the Internet with the force of a tank battalion.
Some have suggested it is preparation for the imminent declaration of martial law. Others, noting recent warnings that the Islamic State militant group could pose a threat on U.S. soil, suggest that the Army is preparing to wage a "holy war" along the southern Arizona border.
With his state up in arms, U.S. Sen. Ted Cruz (R-Texas), who is running for president, said he had reached out to the Pentagon to "inquire" about Jade Helm 15 and said he had "no reason to doubt" assurances that it is a military training exercise.
At the same time, he told Bloomberg Politics during a political event in South Carolina, "I understand the concern" raised by citizens.
"It's a question I'm getting a lot, and I think part of the reason is we have seen, for six years, a federal government disrespecting the liberty of the citizens. And that produces fear, when you see a federal government that is attacking our free speech rights, or religious liberty rights, our 2nd Amendment rights, that produces distrust as to government," Cruz said.
Pentagon officials have sought to calm the storm.
"We have given information to authorities in Texas, any information that they've requested—we've been very open and upfront about our training activities in the United States," Defense Secretary Ashton Carter told reporters Thursday. "We've tried to be very transparent in this case, answer all questions...about what we're doing, about the need for it."
Later, a reporter put it to Carter directly: "Is the U.S. military planning to overtake Texas, as is being asserted by some presidential candidates?" he was asked.
"No," Carter replied.
The exercise will feature thousands of special forces troops, including Green Berets, Army Rangers and Navy SEALs, simulating combat missions on public and private land in five states, with non-special-forces personnel operating in two additional states.
It is intended as "routine training to maintain a high level of readiness" for special forces, commanders said in their announcement of the exercises, "since they must be ready to support potential missions anywhere in the world at a moment's notice."
The map dividing the Southwest into "hostile" and "permissive" states, which Jones' website claims is "detailing the U.S. Army's plan to wage war on the American people," has been widely circulated on the Internet as part of a purported U.S. Army Special Operations Command document describing "realistic military training" aims for Jade Helm 15.
The Washington Post said it had verified the authenticity of the document via unidentified Army sources who said the briefing paper had been prepared to brief local officials on the exercises.
Not all local officials are alarmed.
Former Texas Lt. Gov. David Dewhurst published an op-ed piece in the Dallas Morning News on Thursday urging citizens to support the military in its efforts to train troops.
"Unfortunately, some Texans have projected their legitimate concerns about the competence and trustworthiness of President Barack Obama onto these noble warriors," Dewhurst wrote of the recent controversy.