The US government could shut down this weekend. Here’s what to know.

A federal shutdown is looking likely in the wake of a Republican revolt against a proposed spending bill, as a weekend deadline looms.

If Congress can agree on a new spending measure before the end of the week, agencies will be funded until mid-March. But without new legislation, crucial services and legions of federal workers will be sidelined or go unpaid after 12:01 a.m. Saturday.

Here’s what you need to know about the possible effects of a government shutdown.

What is a government shutdown?

The federal government can only spend money that has been appropriated by Congress — that is, spelled out in a funding law. If Congress cannot agree on the bill that will finance the government before the current one expires, it creates a gap in government funding. Then Congress must approve new short-term funding, or else agencies have to shut down.

There have been more than 20 government shutdowns sparked by funding gaps. Now lawmakers have mere hours to avert another one.

Why is the government about to shut down again?

Congressional leaders had lined up on Tuesday to approve a short-term spending bill that would avert a government shutdown. Negotiated by House Speaker Mike Johnson (R-La.) with Democrats, the extension, called a continuing resolution or CR, would have pushed the deadline until March 14 and included more than $100 billion in aid for natural-disaster survivors, bipartisan health care policy changes and other unrelated provisions.

But on Wednesday, Elon Musk, head of the nongovernmental “Department of Government Efficiency,” launched a vociferous campaign against the spending bill, which seems to have turned the tide in Washington. Musk, sometimes boosting false claims on X, the social media site he owns, trashed the bill in an hourslong tirade, calling it “terrible,” “criminal,” “outrageous,” “horrible,” “unconscionable,” “crazy” and, ultimately, “an insane crime.”

Later that day, Republicans rejected Johnson’s proposal.

Now, with hours waning before the deadline, there seems to be no clear path forward.

How long would a government shutdown last?

A shutdown could be relatively short, though it’s nearly impossible to know in advance. Because the deadline hits on a weekend, if the government does shut down, lawmakers have some time to try to resolve things while most federal workers are already off the clock. If lawmakers miss the midnight deadline, they could still pass funding legislation later Saturday or Sunday and have the government open again on Monday like nothing ever happened. In this scenario, a partial shutdown might last only a few hours, if final passage of new funding legislation comes Saturday morning, or about a day, if it happens Sunday.

The shortest government shutdown lasted just a few hours.

Lawmakers are set to leave Washington for 16 days at the end of the week, so the prospect of cutting into that break might also encourage them to wrap up speedily — and few of them will want to miss Christmas, which falls on Wednesday, to deal with spending legislation.

How will federal agencies deal with the shutdown?

Not all of the agencies and departments whose funding will run out would see the same effects — and most wouldn’t shutter completely. Activities that are considered essential to public safety, economic stability and the president’s constitutional authority continue during a shutdown. For example, Transportation Security Administration officers would stay on the job, but go unpaid, as would the United States’ roughly 1.3 million active-duty military service members.

Who would be affected by a government shutdown?

A government shutdown that lasts past the weekend would affect a wide range of crucial federal services and thousands of employees.

Millions of federal and military employees could be hit with paycheck delays, though that depends on how long a shutdown lasts.

The IRS — which historically has been among the most aggressive federal agencies in curtailing operations when federal funding lapses — says it will furlough more than half its nearly 90,000 employees if a shutdown happens.

Most government employees who are crucial to travel safety would continue working without pay during a government shutdown, but that designation varies by agency.

All but about 3,000 of the TSA’s more than 60,000 employees will stay on the job, according to the agency’s most recent shutdown plan.

The State Department will continue issuing passports and visas in the United States and abroad, the agency said, because the work is considered essential to national security, and most funding is covered by the fees that passport applicants typically pay.

Some passport locations, however, are in government buildings run by agencies more deeply affected by a government shutdown. If those buildings are closed, the State Department might suspend consular and passport services, it said in its contingency plan.

Do national parks close in a government shutdown?

Yes. Closed national parks and Smithsonian museums in Washington are often the most visible early signs of a government shutdown.

“In general, National Park Service sites will be closed during the period of a lapse in appropriations,” the agency notes in its contingency plan. “The majority of National Park sites will be closed completely to public access.”

The public should stay away from parks during a shutdown, including “areas that by their nature are physically accessible to the public” the plan states, because these areas will “face significantly reduced visitors services.”

Will payments to Social Security recipients be affected?

No. Entitlements such as Social Security and Medicare have their own funding vehicles that are separate from the appropriations currently in question. The Social Security Administration’s latest contingency plan for a lapse in funding says it will maintain activities “needed to ensure accurate and timely payment of benefits.”