If a government shutdown is coming, it's going to hit the IRS hard.

Nearly 90 percent of the tax collection agency's workforce would be furloughed if President Trump and congressional Democrats can't agree on a bill to keep a handful of federal agencies open past Dec. 21.

Trump and his Democratic foes in Congress indicated this week that they aren't close to a deal. Nancy Pelosi, D-Calif., and Chuck Schumer, D-N.Y., were openly feuding with Trump in the White House on Tuesday as they rejected his push for another $5 billion to fund a border wall.

In response, Trump said he'd be "proud" to have a partial government shutdown as the result of his stand for border security.

The public brawl seemed to boost the chances of a failed negotiation, in which case IRS operations would be severely curtailed.

The Treasury Department updated its shutdown contingency plan less than two weeks ago. The update sketches out a temporary plan through the end of Dec. 31.

Treasury designates any dates outside of Jan. 1 through April 30 as "outside the filing season," and, as a result, furloughs of IRS workers would be greater through the end of December if a funding deal falls apart.

Specifically, Treasury said 9,946 of the nearly 80,000 IRS workers would be furloughed. That would leave only about 12 percent of the IRS workforce at work during a shutdown, and the remaining 88 percent would stay home.

The giant cut to the IRS would likely become less severe if the shutdown lasted into 2019, because that would enter the new tax filing season.

The IRS is part of the Treasury Department, one of the agencies that doesn't have its full-year funding yet and is therefore susceptible to a shutdown. In prior shutdowns, as much as 83 percent of Treasury Department officials were furloughed.

Much of the rest of the government has already seen their spending bills passed into law — the Departments of Defense, Veterans Affairs, Health and Human Services, and others aren't at risk.

But others are at risk, like the Departments of Commerce, Interior, and Housing and Urban Development. In past shutdowns, at least three-quarters of workers in those agencies were furloughed, and in HUD's case, it was about 96 percent of all employees.

Other departments that still don't have funding deals in place, like the Departments of Justice and Homeland Security, won't be hit as hard because they have more "essential" employees who won't be furloughed.

In this year's earlier and very brief shutdown, just 17 percent of the Justice Department's workers were furloughed. The department's latest plan says most criminal litigation would continue, and that civil litigation would be reduced "to the extent possible without compromising public safety or the protection of property."

DHS is also largely immune, as just 13 percent of its workers would be deemed "non-essential."

DHS estimates that of its 242,136 workers, 212,220 would be exempt from the shutdown.