A partial government shutdown in the coming days would cause federal workers to be furloughed and many high-profile government services to lapse, unless Congress and President Trump quickly enact legislation to fund the government.

That’s what has happened in past shutdowns, such as the one that occurred under former President Barack Obama and the Republican-controlled House in October 2013.

On Friday, Office of Management and Budget Director Mick Mulvaney, responsible for planning for a shutdown, said he would aim to minimize the impact of a lapse in government funding.

“We are going to manage the shutdown differently,” he said, claiming that the Obama administration had “weaponized” the 2013 shutdown by making it as costly as possible. In the 2013 shutdown, in one memorable instance, officials roped off the National World War II Memorial on the National Mall, prompting a showdown between visiting veterans and the National Park Service.

At the peak of the shutdown, according to the Obama budget office, roughly 850,000 employees were furloughed each day, about 40 percent of the federal civilian workforce.

Many government programs would continue throughout a shutdown because they don’t need new legislation from Congress to receive funding, but instead automatically get funding as expenses arise. Medicare and Social Security fall into that category. Others get funding from user fees, and thus would avoid shutting down in the case of a lapse in funding.

Only the parts of government that are funded through the annual appropriations process — meaning through bills passed by Congress each year — would be subject to the shutdown.

Even within that category, many activities will continue because they are judged as necessary for national defense or public safety.

But for government services such as the National Park Service, the Internal Revenue Service, and the Environmental Protection Agency, the shutdown would hit workers hard.

Each agency is supposed to prepare for a shutdown to determine which employees would stay on to take care of which responsibilities, subject to the guidance of OMB and the requirements of the laws underlying government procedures.

Later Friday afternoon, the OMB sent agencies a letter telling them that "prudent management requires that agencies be prepared for the possibility of a lapse" and reminding them of how to do that.

Mulvaney suggested Friday that he would use more tools to keep workers on the job, such as allowing agencies to draw on unused funds or to move funds around. He also hinted at allowing more federal workers to do their jobs without being paid, a maneuver limited by law.

“The military will still go to work. They will not get paid. The border will still be patrolled. They will not be paid. Fire ... folks will still be fighting the fires out west. They will not get paid. The parks will still be open, people won’t get paid,” he said.

Typically, federal workers receive back pay after the shutdown is over for the time they spent furloughed, although that isn’t required by law.