What happens now the US government has shut down?

The US Capitol - AP
The US Capitol - AP

Congress failed to pass a spending bill by Friday at midnight, triggering a shutdown of the federal government.

The move has big repercussions for America. US troops will continue their duties, and post will get delivered, but almost half of the two million civilian federal workers would be barred from doing their jobs.

Here's a look at what it means to shut down the government.

Intelligence work will be scaled down

The workforce at the 17 US intelligence agencies will be pared down significantly.

An official said employees who are considered essential and have to work will do so with no expectation of a regular pay cheque.

While they can be ordered to stay on the job, federal workers can't be paid for days worked during a shutdown. In the past, however, they have been paid retroactively even if they were told to stay at home.

National Parks and museums

The Smithsonian museums in Washington, and the National Zoo, which are huge tourist attractions, will close from Monday if the shutdown continues.

First Lady Melania Trump at the Smithsonian National Museum of American History  - Credit: AFP
First Lady Melania Trump at the Smithsonian National Museum of American History Credit: AFP

Staff will continue to feed animals at the zoo but the well-known Panda Cam will cease broadcasting.

The Interior Department said that in the event of a government shutdown, national parks and other public lands will remain as "accessible as possible". 

That position is a change from previous shutdowns when most parks were closed and became high-profile symbols of dysfunction.

Heather Swift, a spokeswoman, said the American public - especially veterans who come to the nation's capital - should find war memorials and open-air parks available to visitors. Ms Swift said many national parks and wildlife refuges nationwide will also be open with limited access when possible.

She said public roads that were already open are likely to remain open, although services that require staffing and maintenance such as campgrounds, full-service restrooms and concessions won't be operating. Backcountry lands and culturally sensitive sites are likely to be restricted or closed, she said.

Panda Cam - Credit: Reuters
Panda Cam would stop broadcasting Credit: Reuters

Health research disrupted

Dr Anthony Fauci, infectious disease chief at the National Institutes of Health, said a government shutdown will disrupt research and morale but will not adversely affect patients already in medical studies.

"We still take care of them," he said of current NIH patients. But other types of research would be seriously harmed.

A shutdown could mean interrupting research that's been going on for years, he said. The NIH is the government's primary agency responsible for biomedical and public health research, ranging from cancer studies to the testing and creation of vaccines.

"You can't push the pause button on an experiment," he said.

Law enforcement training to be cancelled

Many of the nearly 115,000 US Justice Department employees have national security and public safety responsibilities that allow them to keep working during a shutdown.

So will special counsel Robert Mueller's team investigating allegations of Russian meddling in the presidential election. His office is paid for indefinitely.

Criminal cases will continue, but civil lawsuits will be postponed as long as doing so doesn't compromise public safety. Most law enforcement training will be cancelled, according to the department's contingency plan.

Visas could be disrupted

Tillerson - Credit: Reuters
Grounded? Rex Tillerson Credit: Reuters

Heather Nauert, State Department spokeswoman. said security for American diplomats overseas wouldn't be affected.

But no decision had yet been made about what services, such as visa processing and passports, the State Department would be able to provide.

Nor had there been a decision about whether Rex Tillerson, the Secretary of State, could go ahead with a planned trip to Europe next week if the government closed.