Pentagon officials are preparing to furlough nearly all of the department's civilian workforce, severely curtail day-to-day U.S. military operations and bring any plans for new business contracts to a halt if the federal government shuts down next week.
The shutdown plan, drafted by Deputy Defense Secretary Ashton Carter and released Friday, closely follows the Defense Department contingency blueprint issued by military leaders in anticipation of the last shutdown threat in 2011.
Despite those sharp reductions, department and service leaders will continue to carry out "essential operations in the absence of appropriated funds," Carter said in a memorandum Friday.
"The department will, of course, continue to prosecute the war in Afghanistan ... as well [as] continue many other operations necessary for the safety of human life and protection of property," Carter said in the Pentagon-wide memo.
On Friday, the Senate voted along party lines to pass a stopgap spending measure lasting until Nov. 15 after removing controversial language to defund ObamaCare.
The 54-44 vote puts the Senate on a collision course with the House, where Speaker John Boehner (R-Ohio) has said the stripped-down bill would not reach the floor.
If Congress does not resolve the impasse by Tuesday, funding will expire, and many government services would be limited.
But merely planning for a potential shutdown is already having a negative impact on the Department of Defense.
"The planning itself is disruptive," Pentagon Comptroller Robert Hale said Friday.
Top DOD offices are wasting "thousands of hours of employee time" that could be used to address pressing national security issues facing the United States, Hale told reporters at the Pentagon.
"I am in triage mode," Hale said, describing the department's efforts to prepare for a looming shutdown.
That said, "I hope we are all wasting our time" in preparing for a shutdown, Hale said, adding that Congress needed to take action immediately.
Carter listed more than 40 essential Pentagon and service-led activities that would be exempted from a possible government shutdown on Oct. 1.
Nearly all of those activities on the exempted list are "determined to be necessary for national security," according to Carter.
Aside from combat operations in Afghanistan and elsewhere, the national security missions on the list range from ongoing intelligence operations to maintaining dining halls and gyms "required for readiness" of U.S. forces.
Should the White House order combat operations, such as military action in Syria, that mission and others would also be exempted from the effects of a shutdown, Hale added.
As a result, all U.S. service members "will continue to report for duty," even if the federal government shutters its doors on Monday.
Those soldiers, sailors, airmen and Marines will carry out their assigned jobs, as well as pick up additional work left behind by furloughed civilians, according to the Pentagon guidance.
"A minimum number of civilian employees may be retained as needed," but only to oversee the shutdown of those day-to-day operations deemed unnecessary by Defense Department leaders.
Roughly 400,000 civilian employees — half of the entire civilian workforce — would be sent home from the Pentagon and other DOD installations as a result of a shutdown, Hale said.
"I would expect [civilian furloughs] to be in that vicinity," Hale added.
Pay for civilians who are furloughed would come only if Congress passed a law approving it, Pentagon press secretary George Little said last week.
While service members would continue to work in the event of a shutdown, their paychecks would be delayed until the shutdown ends.
However, Carter and Defense Secretary Chuck Hagel held out hope congressional lawmakers would be able to reach an eleventh-hour deal to avoid a shutdown.
"Secretary [Hagel] and I hope the Department of Defense will receive a [continuing resolution]" before the Oct. 1 deadline, Carter said.
Friday's Pentagon guidance "is intended to support prudent planning" for a shutdown, and not in anticipation of a guaranteed outcome, he added.
— This story was originally posted at 2:11 p.m. and has been updated.