North Carolina's U.S. senators are sounding an alarm when it comes to training at Fort Bragg.
A copy of the letter was provided to The Fayetteville Observer.
"In the last few months we have engaged all levels of leadership in the 18th Airborne Corps from commanding generals to first sergeants," the letter reads. "To a man, we have received the same message -- the corps' airborne qualifications are degraded, units are not getting the support they require."
Officials from the 18th Airborne Corps are working on a response to the Observer's questions about the letter.
The senators link the lack of support to the Air Force decision to eventually shutter the 440th Airlift Wing, an Air Force Reserve unit at Fort Bragg's Pope Field.
They compared that decision to a failed business model.
"In no successful enterprise would a supplier or provider of support dictate to the customer how and when such support is delivered," they wrote. "More specifically, the Army would never offer an opinion as to how the Air Force runs a bomber base, nor should the Air Force prescribe to the Army Airborne how and when it can train its paratroopers."
The 440th Airlift Wing was marked for inactivation in March 2014, but the actual closing has been delayed several times.
In July, Air Force Reserve Command confirmed it had pushed back the inactivation of the unit until at least fall 2016.
But officials had already begun to move airmen from the unit, which has made an impact on the support Fort Bragg's lone airlift unit can provide to the 82nd Airborne Division, 18th Airborne Corps and other paratrooper units.
The Air Force's plans call for outside units to fill in for the 440th, flying crews to post for training events.
But Tillis and Burr's letter said the Air Force's own plan shows "they cannot meet Fort Bragg's daily training requirements if the indigenous Air Force lift presence disappears."
The senators want Milley to "engage leaders at the Department of the Air Force and question them as to why they are failing to live up to their commitment to ensure American troops are properly trained and ready for combat."
They note Fort Bragg's unique role as home to the nation's quick reaction force, the Global Response Force, which is tasked with deploying anywhere in the world on short notice for combat or humanitarian missions.
The senators said the loss of the 440th Airlift Wing "would undermine the training and readiness of America's Global Response Force."
Past leaders of Fort Bragg and the 18th Airborne Corps have questioned the closure of the 440th Airlift Wing, and Air Force officials have previously said they did not consult with Army leaders before moving forward with their plans.
Local leaders also have protested the move, seeking the support of Tillis, Burr and other congressional leaders who have offered numerous bills in attempts to save the unit.