Federal departments and agencies were gearing up for the possibility that a shutdown would actually take place, with Office of Management and Budget Director Mick Mulvaney putting the odds at about 50-50 Friday morning.

The effects across the government would vary from agency to agency, in part because they have different levels of available funding and transfer authority, but Mulvaney said a partial shutdown starting Saturday would in some ways not resemble the one in 2013.

“They could have made the shutdown in 2013 much less impactful, but they chose to make it worse. The only conclusion I can draw is they did so for political purposes. So it will look different this time around,” Mulvaney said.

An OMB official told Roll Call that agencies are being directed to comply with the law barring the improper spending of funds without appropriations, known as the Antideficiency Act, but not to inflict undue hardship.

The Mulvaney-led OMB asked for departments to look at their plans last year, just in case of a shutdown. One change, according to an OMB official, is that National Park Service lands will be open and private vendors will be working, but some federal services like maintenance of the bathrooms and trash removal will be suspended.

McConnell, Durbin Make Their Case As Shutdown Looms

Roughly half the employees at the Department of Health and Human Services would be furloughed in the case of a partial government shutdown, according to a document outlining the department’s contingency staffing plans for the current fiscal year in the case of lapsed appropriations.

Over at the Internal Revenue Service, where work is under way on drafting implementing guidance for the 2017 tax code overhaul.

The IRS filed a contingency plan in effect during the tax filing season, which sees the agency keeping 43.5 percent of its employees working during a government shutdown.

The agency would furlough about 45,500 of its 80,600 employees.

Elsewhere in the federal bureaucracy, the bulk of employees are likely to continue to work.

For instance, the vast majority of Homeland Security employees will remain on the job if the government shuts down, a department spokesman said Friday.

“The dedicated men and women of DHS are fully prepared to protect the homeland and keep Americans safe should a lapse in government funding occur,” a DHS official said in an an emailed statement. “Nearly 90 percent of all DHS personnel are considered essential staff and will continue to perform their duties in the event of a government shutdown.”

Personnel directed to work throughout the government generally would not be paid until a resumption of appropriations. That includes members of the armed services.

“The department will, of course, continue to prosecute the war in Afghanistan and ongoing operations against al-Qaida and the Islamic State of Iraq and Syria,” wrote Deputy Defense Secretary Patrick Shanahan in 14 pages of guidance on preparing for the looming shutdown.

Mulvaney said Friday that even with the potential for less pain should appropriations lapse, Congress still needs to act quickly.

“The Post Office will be open. The TSA will be open,” he said. “But again, all of these people will be working for nothing, which is simply not fair. We are going to manage the shutdown differently. We are not going to weaponize it. We’re not going to try and hurt people, especially people who happen to work for this federal government. But we still need Congress to appropriate the funds.”

John T. Bennett, Dean DeChiaro, Doug Sword, Mary Ellen McIntire, Andrew Siddons and Rachel Oswald contributed to this report.