Who keeps working — and who doesn't — if the government shuts down next week

• Last government shutdown may have cost U.S. economy $20 billion
• Private businesses take a hit, too

Here we go again.

When Congress comes back from recess Monday, it has just five days to head off yet another government shutdown by the end of next week, when the U.S. Treasury officially runs out of the legal authority to spend money.

That deadline will set up another showdown — this time with a new president and fractured Republican Party — that could once again inflict fiscal chaos and force federal agencies to suspend services and send workers home.

So far, the threat of a shutdown appears low, as the GOP seeks to avoid the kind of backlash that accompanied the 16-day stalemate of October 2013. That debacle cost the economy more than a billion dollars a day, according to most estimates.

But the ongoing dysfunction in Congress — evidenced by the GOP's failed effort to repeal and replace Obamacare — are giving some analysts pause.

"That failure taught us that we can't rule out intraparty skirmishes in addition to the usual clashes between the parties," said Greg Daco, chief U.S. economist at Oxford Economics.

If Congress once again shoots itself in the fiscal foot, the resulting gridlock would be inconvenient and costly for taxpayers.

On the other hand, the disruption — even if a shutdown lasts only a few days — would be painful and widespread.

Who keeps working, and who doesn't

Some benefits, like unemployment insurance and veterans' benefits, could be delayed or reduced. National parks, museums and many passport offices would shut down; the Small Business Administration and FHA would stop guaranteeing new loan applications; farm subsidy checks stop flowing and IRS tax processing would slow down, among other headaches.

If you're applying for a mortgage and the bank wants to verify your tax return, you may be out of luck. Social Security checks would go out, but recent retirees would have to wait to sign up. Though U.S. military troops would continue serving, some might have to wait to get paid.

And the Commerce and Labor departments would be shut down, which would delay their data releases, creating a hardship for economists and investors.

Some of the more than 2.2 million government workers would be exempt from furlough, including those who provide essential services.

NSA agents would keep snooping on phone calls, TSA screeners would keep examining luggage and air traffic controllers would show up for work, along with food safety inspectors, border patrol officers and federal prison guards, most FBI agents, doctors and nurses at the VA and other federal hospitals, and any federal emergency and disaster relief workers.

The U.S. Postal Service, which is funded separately, would continue to deliver the mail. And Federal Reserve officials would continue to go to work, because they draw paychecks from funds generated by interest on the central bank's assets.

2013 shutdown cost $20 billion: Moody's

Though past shutdowns have been short, it doesn't take long for the cost to add up.

Last time around, some deferred business was made up in the weeks and months after the government opened again for business. But other losses were permanent.

Nongovernment businesses catering to tourists visiting national parks, for example, suffered permanent losses on hotel bookings. Realtors reported that some home sales were canceled because of delays in mortgage approvals.

Estimates of the total tab varied. Moody's estimated that the 2013 shutdown slashed about $20 billion from overall gross domestic product, or about half a percentage point, in the fourth quarter of that year.

The ratings agency estimated that about 400,000 federal employees were furloughed, another 1.2 million federal employees worked but were paid late, and "a couple of hundred thousand private sector employees, many at defense contractors, could not work because of the shutdown and are unlikely to receive back pay."

Budget Band-Aid

Congress is supposed to pass an annual budget — usually through multiple spending bills for various government agencies and functions — well before the end of the fiscal year, which falls on Sept. 30.

When the process breaks down, as it has done frequently in the past decade, the only way to keep the government funded is through what's called a continuing resolution.

The measure amounts to a budget Band-Aid, giving federal agencies authority to keep spending what they're already spending for a few more weeks or months.

The current continuing resolution, passed in December, runs out at midnight next Friday at midnight, a deadline that both sides of the aisle could use to fight policy battles. Bills have already been introduced to use the budget process to advance measures opposing abortion and to block construction of President Donald Trump's proposed border wall.

Watch: OMB director says chance of shutdown low