The Pentagon would need to furlough “virtually all” of its nearly 800,000 civilian employees for one month between March and September if mandatory federal spending cuts go into effect in March, according to a prominent defense budget analyst.

The analysis by Todd Harrison, a defense spending expert with the nonpartisan Center for Strategic and Budgetary Assessments, is the latest chapter in the ongoing fiscal spending saga that has stymied Washington for more than a year.

“This will have a very real impact if [sequestration] goes into effect,” Harrison said during a Jan. 9 briefing in Washington. “One of the first things we’ll see, DoD will have to start furloughing civilian employees.”

Last week, the White House and Congress reached a deal to avert tax increases for the majority of American citizens. But cuts to DoD and other federal agencies — known as sequestration — were delayed from January until March in hopes lawmakers and President Obama could agree on a comprehensive plan to reduce the federal deficit.

Under the new deal, the 2013 impact of sequestration on DoD was lowered from about $63 billion to $48 billion, according to Harrison.

The reduction required across all accounts falls to about 9 percent; however, that could fluctuate depending on the amount of unobligated money in each spending account. Military personnel coffers are exempt from the cuts, but count against the budget caps required under the law.

“I’m using an estimate here,” Harrison said. “We don’t actually know the unobligated balances until right before [sequestration] happens.”

DoD would need to furlough basically all of its 791,000 full-time civilian employees to meet the level of cuts mandated by sequestration between March and September, the remainder of the fiscal year. DoD spends about $70 billion per year on pay and benefits for those employees, according to Harrison. Sequestration would cut 8.8 percent from that account.