The Department of Defense is already planning for a government shutdown.
The White House's Office of Management and Budget sent out a memo this week advising agencies to develop a plan.
Part of that includes identifying which services and personnel are needed for essential functions.
A spokesman says a shutdown would result in disruptions similar to those caused by this summer's furloughs.
The Pentagon faced a similar threat in April 2011. That time they developed a plan that included furloughing some 400,000 civilian workers.