WASHINGTON – White House Budget Director Mick Mulvaney says there is a “50-50” chance of a government shutdown late Friday night, while President Donald Trump insists that the U.S. military will suffer the most in a budget crisis.

The House passed a short-term spending bill late Thursday night that would keep the government funded through mid-February and now the Senate has until midnight to strike a compromise to avoid the first government shutdown since 2013.

The Defense Department is one of the largest agencies in government, along with the Department of Homeland Security and the Department of Health and Human Services. Along with overseeing 1.3 million military personnel, the DoD also employs over 740,000 civilian workers who could all be affected if a shutdown were to occur.

While the effects of a shutdown would be felt throughout the government, here are four things to know about how the shutdown would specifically affect the Pentagon.

1. The military will not stop operating

All uniformed military personnel will continue to work through the weekend and will report to work on Monday, while military operations abroad will continue. However, there is chance that many active military and civilian employees will not be paid for their work until the shutdown ends.

Undersecretary of Defense David Norquist highlighted this fact in a December Pentagon press briefing. “No one gets paid,” Norquist said. “The civilians who report to duty do not get paid. The military who are in theater do not get paid.”

However, Susanna Blume of the Center of New American Security – who worked for DoD when the 2013 shutdown occurred – said that Congress could always appropriate funds for military personnel after a shutdown to make them whole. In 2013, Congress passed the Pay Our Military Act at the last minute that allowed for military and certain civilian personnel continue to work and be paid during the that year’s shutdown.

If another shutdown were to occur late tonight, Congress could pass a similar bill.

2. Civilians employed by DoD may be sent home

Blume said that all civilian employees would report to work on Monday. Those deemed essential would continue to work while the rest would be sent home

Norquist said that these determinations would fall under what is called “excepted activities,” which include things like “safety of property” and “protection of life.” These are also the terms that are outlined by the government’s Office of Personnel Management.

A few days after passage of the 2013 legislation that funded payment of military members, a provision was added to also cover a certain number of civilians who were employed by DoD, Blume said.

There is guidance in place that help determine what is excepted and what is not. However, the department cannot make plans too detailed because of the different conditions that Congress can make in the event of a shutdown.

“There’s only so much advanced planning that you can do,” Blume said.

3. Certain contracts made by DoD will go unpaid

The payment of contractors would be handled on a case by case basis – dependent on the type of contract that it is and how it was written. Some are paid in advance, some are paid over time, and some are written for payments to take place on specific dates.

Because of this complexity, it is hard to say broadly what happens.

Norquist explained that contracts made by DoD that are operating will be subject to the same “excepted activities” assessment that civilians are subjected to. Contracts that relate to the “protection of life and protection of property” – like contracted air support in a theater of operation – would go unpaid, but they would continue to operate.

4. Other functions of the department, like the payment of family death benefits, will go unpaid as well

One example of non-payment cited by Norquist was the payment of death benefits to the family of military members killed in action.

“We’re not allowed to make those payments until the shutdown ends,” Norquist said.

Blume explained that this could be something that Congress decides to cover in the event a shutdown happens. But, in 2013, these families were not provided with benefits from the government that can help pay for things like funeral arrangements and travel. However, a charity group, the Fisher House Foundation, restored death benefits to families of service members killed in action, according to The New York Times.