A primer on what the shutdown means to federal employees and agencies

Federal agencies are legally required to furlough their "nonexcepted" employees during the government shutdown. Excepted employees, who include those who work to protect life and property, stay on the job but do not get paid until after the shutdown ends.

The White House Office of Management and Budget begins the process with instructions to agencies that a lapse in appropriations has occurred and they should initiate orderly shutdown activities. That memo went out Tuesday evening.

The Congressional Budget Office estimates roughly 750,000 federal employees could be furloughed each day of the shutdown, with the total daily cost of their compensation at roughly $400 million.

What government work continues during a shutdown?

FBI investigators, CIA officers, air traffic controllers and agents operating airport checkpoints keep working. So do members of the armed forces.

Those programs that rely on mandatory spending generally continue during a shutdown. Social Security payments still go out. Those relying on Medicare coverage can still see their doctors and health care providers can be reimbursed.

Veteran health care continues during a shutdown. Veterans Affairs medical centers and outpatient clinics will be open, and VA benefits will be processed and delivered. Burials will continue at VA national cemeteries.

Will furloughed federal workers get paid?

Yes. In 2019, Congress passed a bill enshrining into law the requirement that furloughed employees get retroactive pay once operations resume.

While they eventually will be paid, the furloughed workers and those who remain on the job may have to go without one or more of their regular paychecks, depending upon how long the shutdown lasts.

Service members would also receive back pay for missed paychecks once federal funding resumes.

Will I still get mail?

Yes. The U.S. Postal Service is unaffected by a government shutdown. It’s an independent entity funded through the sale of its products and services, not by tax dollars.

What closes during a shutdown?

All administrations get some leeway to choose which services to freeze or maintain in a shutdown.

The first Trump administration worked to blunt the impact of what became the country’s longest partial shutdown in 2018 and 2019. But on Tuesday, Trump threatened the possibility of increasing the pain that comes with a shutdown.

"We can do things during the shutdown that are irreversible, that are bad for them and irreversible by them," Trump said of Democrats. "Like cutting vast numbers of people out, cutting things that they like, cutting programs that they like."

Each federal agency develops its own shutdown plan. The plans outline which workers would stay on the job during a shutdown and which would be furloughed.

What agencies are planning

The Department of Health and Human Services will furlough about 41% of its staff out of nearly 80,000 employees, according to a contingency plan posted on its website.

As part of that plan, the Atlanta-based Centers for Disease Control and Prevention would continue to monitor disease outbreaks, while activities that will stop include research into health risks and ways to prevent illness.

Meanwhile, research and patient care at the National Institutes of Health would be upended. Patients currently enrolled in studies at the research-only hospital nicknamed the House of Hope will continue to receive care. Additional sick patients hoping for access to experimental therapies can’t enroll except in special circumstances, and no new studies will begin.

At the Food and Drug Administration, its "ability to protect and promote public health and safety would be significantly impacted, with many activities delayed or paused." For example, the agency would not accept new drug applications or medical device submissions that require payment of a user fee.

The National Park Service plans to furlough about two-thirds of its employees while keeping parks largely open to visitors during the federal shutdown, according to a contingency plan released Tuesday night. The plan says "park roads, lookouts, trails, and open-air memorials will generally remain accessible to visitors."