The government is on the brink of shutting down again.

Congress must pass another stopgap budget to fund federal programs past Thursday at midnight. If a deal isn't reached, troops, veterans, and their families could face another government shutdown just weeks after the last one. That could again leave some uniformed servicemembers without paychecks or access to some on-base services.

Here's how another shutdown would affect military operations, pay, and access to medical care.

Who's on duty? All military personnel remain on active duty during government shutdowns, continuing to carry out their normal roles. Active duty troops' duties won't be affected if some portions of the government close, according to a 2016 Pentagon memo about funding lapses.

That's not true for all civilian DoD employees though. Only those whose roles “are necessary to carry out or support expected activities” would be asked to come to work. The rest would be furloughed, meaning they'd be placed in a nonwork, nonpaid status.

Last month, training for more than 110,000 Guard and reserve personnel was unexpectedly canceled after the government shut down, Military.com reported. Those servicemembers had to pay their own travel costs to head back home, but were told they'd likely be reimbursed when the government reopened.

Troops' pay. Military personnel and civilian DoD employees shouldn't expect to get a paycheck during a government shutdown - even if they're showing up for duty every day.

During the 2013 shutdown, which lasted for more than two weeks, Congress passed legislation that allowed uniformed personnel to receive their paychecks during the shutdown. Since the statute was limited to “members of the Armed Forces,” though, it meant USPHS and NOAA Corps officers were still on duty without pay.

DoD is also under no legal obligation to pay any personnel - military or civilian - during a government shutdown, the Defense Finance and Accounting Service website states.

In 2013, civilian employees who were furloughed weren't paid during the shutdown. Congress later approved back pay for those workers.

Retirees' checks. A government shutdown won't affect payments for retirees or those receiving annuities, like surviving spouses who are paid under the Survivor Benefit Plan, said Steve Burghardt, a spokesman for the Defense Finance and Accounting Service.

Those funds come from a military retirement trust fund, he said. They're not based on the Continuing Resolution Act appropriations, so the payments continue as scheduled.

Families of the fallen. If a servicemember dies during a government shutdown, their families are not guaranteed death benefit payouts, including funds for funeral expenses and the $100,000 gratuity paid to families of the fallen.

MOAA has urged Congress to protect those benefits. The unexpected loss of a servicemember is a traumatic event for any family, and any delay in earned benefits only makes that pain greater, said Col. Dan Merry, USAF (Ret), MOAA's vice president of Government Relations. Congress should find a permanent solution to this problem, Merry added.

Training and operations. The fight against the Islamic State group or other overseas operations won't stop with a government shutdown.

“The Department will, of course, continue to prosecute the war in Afghanistan and ongoing operations against al-Qaeda and the Islamic State of Iraq and the Levant, including preparation of forces for deployment into those conflicts,” the DoD memo states.

Medical care. Servicemembers and their families should still be able to get medical and dental care at on-base facilities even if the government shuts down. They also can seek private-sector care using TRICARE. Elective surgeries or procedures, however, could be postponed or rescheduled.

And while some VA employees could be furloughed, most of the department's facilities and clinics remain fully functional during government shutdowns, according to a VA memo on the topic. Access to in- and outpatient care, prescriptions, surgeries, and mental health appointments likely won't be interrupted.

Some VA hotlines, websites, and claims processes could slow or stop in the event of a government shutdown.

Base and financial services. Morale, welfare, and recreation-related activities are likely to continue if they support military missions. That means mess halls, physical training centers, and childcare activities likely will remain running if they're required for readiness.

If civilian employees who run those facilities or programs are furloughed, though, uniformed personnel will be reassigned to carry out the duties.

DoD has published a list of family support resources. As for families with an upcoming permanent change of station, some moves may be limited in the case of a government shutdown. Troops should check with their commands to make sure everything is still on schedule.

Veterans in the process of buying new homes could face delays in seeing their VA loans go through.

The Office of Personnel Management offers guidance on shutdown furloughs here.