If the federal government were to shut down this weekend, work at numerous publicly funded agencies would be slowed or stopped, while millions of government workers would no longer receive paychecks.

But Social Security benefits would still be eliminated.

Social Security is considered a mandatory program and is not funded by the shorter-term bills that have kept the government running in recent years amid political gridlock in Washington.

About 72.8 million people receive monthly Social Security benefits. These benefits primarily benefit pensioners, but also people with disabilities and relatives of deceased benefit recipients.

While benefit checks continue to expire, people who need to turn to the Social Security Administration for assistance will likely face longer wait times as SSA employees are furloughed. Performance verification, processing overpayments and issuing new cards would also be affected.

SSA staffing levels are already at a 50-year low as House Republicans rejected increased funding for the agency in the continuing resolution passed in September.

Other government benefit programs would not be affected immediately — but could be if the shutdown drags on.

People who received Supplemental Nutrition Assistance, formerly known simply as food stamps, would continue to receive their benefits for 30 days. After that, the program would begin relying on reserve funding, at which point furloughs at the U.S. Department of Agriculture, which administers SNAP, could impact benefit distribution.

Perhaps the biggest threat would be people receiving assistance under the Special Nutritional Supplements Program for Women, Infants and Children, known as WIC. The people receiving assistance under this program are predominantly low-income pregnant women, new mothers and their babies and young children.

There is typically a limited amount of emergency funding available for this program. At that point, WIC administrators begin selecting assistance for individuals with the greatest need.

Numerous other government services have been affected by closures in the past. According to the Committee for a Responsible Federal Budget, the Food and Drug Administration (FDA) delayed nearly 900 inspections during the 2013 shutdown, while the Environmental Protection Agency (EPA) halted inspections for 1,200 sites. National park operations were also severely affected: While many parks remained open, no visitor services were offered, and damage and trash accumulations were reported at many sites, the group said.

Perhaps the biggest potential impact this time would be on air travel as the busy holiday flying season gets underway. During the 2018-2019 shutdown, many travelers experienced extended wait times as Transportation Security Administration employees did not report to work, while ground stops were ordered at major airports such as New York LaGuardia due to a lack of air traffic controllers.

In a statement, a TSA spokesman said its employees were working without pay while handling record volumes over Christmas and New Year’s and that a prolonged closure “could mean longer wait times at airports.”

At some point, a prolonged shutdown would begin to harm the economy. The longest shutdown lasted 35 days, from December 22, 2018, to January 25, 2019, and the Congressional Budget Office estimated it cost the U.S. economy at least $11 billion directly, with indirect costs that were harder to quantify .