The partial shutdown of the U.S. government that began Saturday affects about a quarter of the government. About 800,000 federal workers will feel the effects as lawmakers try to come to an agreement on a set of spending bills to keep the government funded.
A central sticking point remains funding for President Trump's proposed border wall, and with the Senate adjourned until Thursday, there is no apparent quick end in sight.
As both sides work to solve the impasse, here is a rundown of what will and won't be affected by the shutdown.
What is still open and running:
Air traffic control, the TSA and Amtrak
Air traffic control and officers with the Transportation Security Administration will keep working in order to keep air travel running. Amtrak trains will also continue to operate as usual.
Social Security, Medicare and Medicaid
People will continue to receive their Social Security checks, and Medicare and Medicaid will not be interrupted. However, new applicants to these programs might experience a delay before approval.
U.S. military operations will continue around the world. The budget for the Department of Defense has already been approved.
Customs and border agents will continue working along the border and at ports of entry.
The Mueller investigation
Special counsel Robert Mueller's office, which is looking into Russia influence on the 2016 campaign, is "funded from a permanent indefinite appropriation and would be unaffected in the event of a shutdown. ... The appropriation bills before Congress do not touch the (special counsel's office)," a spokesman for the special counsel's office told CNN.
U.S. Postal Service
Post offices will remain open, and deliveries will continue during the shutdown.
Smithsonian museums and the National Zoo
The Smithsonian Institution tweeted that it will continue operation of its museums, research centers and the National Zoo through Jan. 1.
In the event of a #GovernmentShutdown, our museums, research centers and the National Zoo will be OPEN through Jan. 1.— Smithsonian (@smithsonian) December 21, 2018
The Smithsonian can use prior-year funds still available to us to remain open. Smithsonian museums are always closed on Dec. 25.
NORAD Santa tracker
The military says its famous Santa tracker won't be slowed down by the shutdown because it is run by volunteers and funded by the Department of Defense's budget that was approved earlier this year, according to The Associated Press.
What will be affected by the government shutdown:
Some national parks will remain open but may reduce staffing. Facilities such as restrooms may be closed.
"At Yellowstone, Yosemite and many other major parks, the park service announced it would keep the access to parklands open, but many services, including restrooms, trash removal, some visitors centers and snow removal, would cease," The Guardian reports.
Small Business Administration guarantees to back loans will freeze for some business owners.
"Due to the lapse of government funding, SBA will remain inactive until further notice. We apologize for any inconveniences and we look forward to assisting you when we return," the agency posted on Facebook.
"Without workers there to process 7(a) loan applications, which help startups obtain financing, small business owners are forced to find capital elsewhere or wait until Congress and President Trump reach a budget agreement," USA Today reports.
State and local farm service centers
Those operated by the Agriculture Department will be closed, meaning that no staff will be able to assist farmers in signing up for programs under the farm bill recently approved by Congress, The Tennessean reports. The Farm Service Agency assists farmers, ranchers and agricultural partners through delivering U.S. agricultural programs.
Enforcement of fair housing, issuance of new development grants and housing quality inspections will be delayed. Loans for new homebuyers could also stall.
Crime victims and violence against women
"After about one week of a shutdown, the state Department of Commerce would stop getting federal reimbursement for programs that include helping crime victims, stopping sexual violence against women and preventing sexual assault," The Seattle Times reports.
Funding for the Violence Against Women Act has also stopped with the government shutdown.
A previous version of this story referred to a scenario in which military personnel could be affected. Those details are not relevant to the current shutdown because the Pentagon budget has been approved.
NOEL KING, HOST:
This morning, a partial government shutdown continues. It started on Saturday after lawmakers failed to agree on a set of spending bills. The main sticking point was President Trump's demand for $5 billion for border wall funding. The president has stayed in D.C. instead of going off to his resort in Florida, but it's still not clear when the shutdown is going to end. About a quarter of the government is affected. That's 800,000 federal workers. Some of them are furloughed, some of them are working without pay for the moment. NPR's Shannon Van Sant has the story.
SHANNON VAN SANT, BYLINE: The effects of the shutdown will be most noticeable on Wednesday when federal employees were due to return to work after the Christmas holiday. But impacts of the shutdown are already being felt far beyond Washington. Some national parks and monuments are closed.
(SOUNDBITE OF ARCHIVED RECORDING)
UNIDENTIFIED PERSON: Due to the lapse in federal appropriations, Fort McHenry will be closed for the safety of visitors and park resources.
VAN SANT: Others will remain open but with reduced staff and facilities. Tourist Twila Manheim was thrilled to be able to visit the Statue of Liberty.
TWILA MANHEIM: We were really worried because we just drove up from Maine, six of us, for this. And this is our first time, so we're so excited that it didn't shut down, and, you know, I mean, it's going to affect a lot of people but today, not us.
VAN SANT: Core government functions are not included in the shutdown. Air traffic control and Amtrak will keep running. People will still receive their Social Security checks, and U.S. military operations will continue to run around the world. Customs and Border Protection agents will keep working along the border and at ports of entry. And the U.S. Postal Service will deliver the mail as usual. Small businesses may not have access to the Small Business Administration's federally assisted loans as SBA's guarantees to back loans will freeze. State and local farm service centers will be closed and won't be able to assist farmers in signing up for new programs. Tourist Katherine Sharpe says it's time for lawmakers in Washington to make a deal.
KATHERINE SHARP: I think it's pretty ridiculous that a bunch of adults can't come to terms and some sort of compromise to keep the country running.
VAN SANT: In the meantime, 380,000 federal employees will stay home while another 420,000 have been ordered to work without pay. Shannon Van Sant, NPR News. Transcript provided by NPR, Copyright NPR.