At least 800,000 federal workers could get an e-mail or phone call on Friday telling them they are “nonessential.” Just like that, the government can get along fine without them.

Some are crossing their fingers for an order to go home, hoping for some R&R as the deadlock on Capitol Hill continues over how to fund the government. But for most civil servants, it’s demoralizing to think their work does not stack up against 1.2 million others on the federal payroll whose jobs are viewed as more vital to public safety, health and welfare.

Here’s another irritant to would-be nonessentials that’s pushing workers already on edge to make uncomfortable comparisons with colleagues. They’re unlikely to get paid for their forced vacations — a change from the shutdowns of the mid-1990s.

“Everything we do is supporting our sons and daughters overseas,” said Sue McCarl, a Defense Department contract manager in Pennsylvania with a son in the Marine Corps.

“We’re hoping as though we’re essential,” she said. “But I’m not sure how the powers that be are making their decisions. It’s not a comfortable position to be in.”

Many civil servants say they had received only vague missives from agency heads as Friday’s shutdown deadline looms, and no communications from their supervisors about whether employees will be called to work or sent home.

“Should it become necessary to implement our contingency plans, you will receive details from you supervisor regarding your furlough status,” Social Security Commissioner Michael J. Astrue wrote in an employee memo Wednesday afternoon.

Michael Besmer figures his status is a tossup. As someone who authorizes Social Security payments once a dispute or complication is resolved, “what I do is pretty integral to getting benefits out,” he said. “I can’t wait to find out.” He would not be heartbroken, however, to be told his job is not vital.

During budget impasses in the mid-1990s, 284,000 federal workers were furloughed during a three-week shutdown in 1996 and about 800,000 during a shorter outage the previous year. Back then, Congress had passed bills funding various large agencies. None has passed this year, increasing the potential for a larger number of furloughed workers.

After both shutdowns, Congress reimbursed employees who worked and those who didn’t. But union leaders and members of Congress are warning that the national mood to repay workers who stay home would be less sympathetic today.

The Government Accountability Office’s 3,200 employees have been told that beyond the comptroller general, general counsel and a handful of security guards, the auditing arm of Congress would be nonessential. So would employees at the Census Bureau. At the U.S. Army base in Fort Leavenworth, Kan., supervisors on the acquisitions staff would likely be designated essential “because they know the status of all of our programs,’’ said Louis Bornman, an analyst in operations research.

“It’s very demoralizing to think you’re going to be laid off and not be paid,” said Bornman, who is not a supervisor.

Every agency seems to have a different system for deciding who would stay on the job, once the job itself is determined to be essential. The presses that print the Federal Register and other publications of Congress and the White House would keep going. But passports, also printed by the Government Printing Office, would stop.

Let’s say Congress produced a very thin Federal Register requiring fewer printers. “We’ll have to scale down and do it by seniority,” said George Lord, chairman of the 10 union locals representing GPO workers. In this case, though, seniority is not measured by government service, but by the newest worker to become a journeyman.

The union representing workers at the Environmental Protection Agency is demanding that decisions over which employees would remain on the job be decided at the bargaining table under the terms of their collective bargaining agreement.

The Federal Air Marshal Service plans to keep marshals on planes. But it would send home program analysts and budget and administrative staff, and close the Air Marshal academy. In limbo are about 55 IT staffers, of whom 17 would be deemed essential, some in order to schedule air marshals on flights, according to a staffer who was not authorized to speak on shutdown plans.

The decisions on the 17 are not being made based entirely by whose job is most critical to keeping air marshals flying. “There’s a certain human element at play,” the staffer said. “In some cases, it’s ‘I know this person and their spouse works at another government agency, and they both face furloughs, so let’s spare one of them.’ ”

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