(RNN) - President Donald Trump has threatened for months to shut down the government if he doesn’t receive funding for a wall along the U.S.-Mexico border.
The shutdown will only be partial, since about 75 percent of government funding has already been approved for the budget year that started in October, according to the Associated Press.
“I am proud to shut down the government for border security," said the president in a heated meeting Dec. 11 with Senate Minority Leader Chuck Schumer and House Minority Leader Nancy Pelosi.
Who works and who doesn’t?
Nine federal agencies will close in the middle of the holiday season: departments of Agriculture, Commerce, Homeland Security, Housing and Urban Development, Interior, Justice, State, Transportation and the Treasury.
Hundreds of thousands of federal workers will be working without pay during that time, including nearly 54,000 people who help defend the border - Customs and Border Protection agents and customs officers.
The shutdown could affect about 800,000 federal workers in total, according to a report released by Democrats on the Senate appropriations committee. Approximately 420,000 workers will work without pay and another 380,000 will be furloughed.
Workers are exempted from furloughs if their jobs are related to national security or if they perform essential activities that “protect life and property,” according to the Associated Press. The precedent was set by the Reagan administration.
The military should be unaffected by a shutdown, and essential government programs such as Medicare, the postal service and air traffic control would run as normal.
About 41,000 federal law enforcement agents will go on working without pay, including 16,742 prison corrections officers, 13,709 FBI agents and almost 7,000 U.S. Marshals and FBI agents. The U.S. Coast Guard will also go on working.
This will also extend to the Department of Homeland Security, where 88 percent of employees will be working but not receiving a paycheck. This includes the CBP staff and 53,000 TSA employees.
As many as 5,000 Forest Service firefighters and 3,600 weather service forecasters will also continue working, according to the report.
Other federal employees will be granted a leave of absence. National parks may remain open, but about 16,000 employees will be sent home.
About 41,000 Commerce Department staff will be furloughed, as well as staff at NASA and Housing and Urban Development.
In addition, approximately 52,000 IRS staff will be on leave, which may slow down tax returns and audits in the new year.
Democrats warned the shutdown would hamper the efforts of The Emergency Food Assistance Program as well, which provides supplemental food to soup kitchens, food banks and pantries across the U.S.
"The Food and Nutrition Service would not be able to purchase commodities or provide the funding for transportation, distribution, or storage,' they said in their statement. “This could be especially harmful to food banks that receive these commodities at a time when more families rely on their services - the winter and holiday months.”
Important employees who work during government shutdowns have been paid retroactively when the government reopens in previous shutdowns.
There have been a total of 18 government shutdowns since the modern congressional budgeting process took effect in 1976.