WASHINGTON — Operating under a continuing resolution for even three months will impact dozens of procurement and construction projects vital to keeping the military operational, U.S. Defense Secretary Jim Mattis warned top congressional leaders.

In a six-page letter obtained by Defense News, Mattis wrote to Senate Armed Services Committee Chairman John McCain, R-Ariz., outlining the impacts of a CR. An identical letter was sent to other key members of Congress who focus on defense issues.

The Sept. 8 letter was sent two days after two of those key defense lawmakers — Reps. Mac Thornbery and Kay Granger, the Texas Republicans who chair the House Armed Services Committee and the House Appropriations’ Defense Subcommittee, respectively — appeared at the Sept. 6 Defense News Conference to announce that a three-month CR was likely.

Shortly thereafter, a deal was struck to extend the CR to Dec. 8, which has since been signed into law by President Donald Trump. However, the risk remains that a budget deal is not completed by that date, requiring an additional CR.

Also at the Defense News Conference, Pentagon Comptroller David Norquist, making his first public comments since taking office, warned that while the department could once again survive a short CR, the cumulative effect of multiple CRs over the last decade has been “corrosive” for the military.

Highlights from the letter

Mattis first warns of readiness impacts, stating that 90 days after the start of a CR, lost training is “unrecoverable” due to the need to move onto previously scheduled events. As a result, the Marines will lose out on vital training for coordinated joint fires, while the Air Force will be unable to train a group of pilots needed to refresh a pilot shortage.

The Navy will delay induction of 11 ships, which would push some readiness availabilities into fiscal 2019. The service will also reduce flying hours and steaming days, as well as slow down orders of spare and repair parts. The Army, meanwhile, will postpone all noncritical maintenance work orders until later in the year, as well as restricting home-station training.

Overall, no new military construction projects can begin, which will have an “inevitable delay in project schedules and potential increased costs,” Mattis warns. That includes 37 Navy projects, 16 Air Force projects and 38 Army projects.

Infamously, a CR means that no new-start projects can be impacted. For the short-term CR, the Army appears to be the most impacted, with the letter highlighting that there are 18 new-starts and eight production-rate increases that need to be addressed by the end of the year.

The Army’s new-starts impacted include the Paladin Integrated Management improvement project, the Interim Combat Service Rifle program, the Multi-Role Anti-Armor Anti-Personnel Weapon System, the lightweight 30mm cannon and the Armored Multi-Purpose Vehicle.

Rate increases that would be impacted include the TOW 2 missile, an unspecified number of handguns, M240L medium machine guns and the Advanced Tactical Parachute System.

That list increases if the CR drags on longer, as there are 24 new-starts and seven additional production-rate increases the Army needs over the course of the next year. That includes Udairi Range target lifters and the Modular Catastrophic Recovery System, as well as production rates on the Stinger and Avenger weapons.

Both the Navy and Air Force outline their concerns as having more of a six-month deadline. The Navy has seven procurement contracts delayed by a six-month CR, as well as 12 planned production-rate increases and three new-starts in the research and development realm. What those are were not laid out in Mattis’ letter.

The Air Force, meanwhile, has a total of six new-starts that would be impacted by a six-month CR. Those include upgrades to F-15C and F-16 aircraft, as well as the Joint Space Operations Center Mission System.

Although not listed in the letter, Secretary of the Air Force Heather Wilson told Defense News in a recent interview that even a short-term CR would potentially delay the contract award of the service’s new trainer aircraft, known as the T-X.