US government workers face the ultimate performance appraisal next week as America finds out what life would be like without them.

The White House today said only “essential” workers that keep critical functions running will remain on the clock after the midnight Friday shutdown, caused by Congress’s failure to pass a budget in the past 18 months.

But the kicker is who made the “essential” list … 3.6 million of them, or 82%.

A mere 800,000 of the 4.4 million strong federal workforce will go on indefinite leave, but even they may be called back as required, regardless of whether Congress has secured funding.

Even accounting for military personnel, the people who mail the pension cheques, and the other functions the White House promised would continue uninterrupted, those figures are extraordinarily.

Consider what the Office of Personnel Management defines as essential:

“Essential/Excepted” employees include people: (1) performing emergency work involving the safety of human life or the protection of property, (2) performing minimal activities as necessary to execute an orderly suspension of agency operations related to non-excepted activities, or (3) performing certain other types of excepted work.

But for department heads it is like asking how many staff they really did not need in the first place. Or in the great tradition of Sir Humphrey Appleby’s hospital with no patients, it takes almost as many staff to manage a shutdown as it does the full functions of government.

Only the lowest, most surplus of staff will be put on leave, as anyone with an ounce of clout will have found a way to be put on their department’s “essential” list.  The few who couldn’t will be directed to turn off their blackberries — the harshest of time outs in ego-driven Washington.

White House staff and Congressmen will continue to be paid, but all other workers, including military personnel serving in Afghanistan, will not. Some of those workers will be compensated once funding is secured, but not all.

Some Congressmen want their staff to defy the shutdown altogether. Rep Darrell Issa, the self-declared “House GOPs chief watchdog”, figures his committee staff fall under different constitutional rules. Unfortunately for them, the Office of Personnel Management issued a reminder that turning up for work could lead to disciplinary action.

The State Department is expected to be the hardest hit, losing two-thirds of its workforce at the same time as Secretary Hillary Clinton pleads with law makers to fund diplomacy as a way to save money on unnecessary wars.

Washington’s tourists may as well stay home. The city and most of its attractions run almost entirely on federal wages. DC’s beloved Cherry Blossom Parade this weekend was among the first casualties, along with all 19 Smithsonian museums. Worse still, garbage collection is expected to stop (something New York has to deal with almost every month).

The list of what will continue covers almost everything the government does: mail will be delivered, social security will be paid, tax will be collected, and airport passengers’ nether regions will be scanned and groped. Even the government’s twitter accounts are expected to remain active.

This is a far cry from the mammoth shutdowns of the US government in 1995 and 1996. The battle royal between then president Bill Clinton and House speaker Newt Gingrich ultimately cost American taxpayers about $800 million in wages for leave and lost revenue, according to Treasury figures later released by the Clinton administration.

Both sides in Congress say they don’t want a shutdown while accusing each other of not acting like adults. At this point, a shutdown will be difficult, if not impossible to avert. Speaker John Boehner has drafted a one-week extension, which the White House has already rejected. House rules say any budget resolution must be debated for 72 hours, but even if that debate starts immediately won’t beat the shutdown deadline.

A Tea Party rally on Capitol Hill yesterday offered the glimpse into the growing division within the Republican caucus. Small government supporters, who helped give Republicans an overwhelming majority in last year’s election, carried signs saying “Shut’er Down” while their factional leader Rep Michele Bachmann told the crowd a shutdown was not a good idea as it would get blamed on the Tea Party rather than Democrats.