Defense Secretary Jim Mattis warned Friday that even a partial government shutdown would severely impact the U.S. military’s maintenance, training, and intelligence operations.

During a question and answer session Friday Mattis was asked if a shutdown would have “serious ramifications,” for the U.S. military.

“Yes,” he replied and then rattled off several examples.

“I will just tell you that our maintenance activity will probably pretty much shut down,” Mattis said.

“We do a lot of intelligence operations around the world, and they cost money. Those obviously would stop,” he said. “And I will tell you training for almost our entire reserve forces will stop. And you must understand the critical importance of our reserves. They are the only shock absorber we have.”

Mattis said 50 percent of the Defense Department's civilian workforce would have to be furloughed, including people who handle projects “that keep me at the top of my game.”

But Mattis warned the biggest impact may be psychological. “It’s got a huge morale impact,” he said. “How long can you keep good people around when something like this happens is always a question that has to hover in the back of my mind.”

During his prepared remarks in which he outlined the Pentagon’s new National Defense Strategy, Mattis repeated a line he has used many times before about the damaging impact of federal spending caps.

“As hard as the last 16 years of war have been, no enemy in the field has done more to harm the readiness of the U.S. military than the Combined impact of the Budget Control Act’s defense spending caps, and 9 of the last 10 years operating under Continuing Resolutions, wasting copious amounts of precious taxpayer dollars.”

“As I stand here this morning, watching the news off the Hill, we’re on the verge of a government shutdown or, at best, yet another debilitating continuing resolution,” Mattis said. “We need Congress back in the driver’s seat of budget decisions, not in the spectator’s seat of the Budget Control Act’s indiscriminate and automatic cuts.”