The government halts operations if Congress doesn’t pass a full-year funding bill or a temporary measure like a continuing resolution (CR). Without those measures, the Antideficiency Act requires that federal agencies cease activities unless they are deemed essential. During a shutdown, nonessential staff are furloughed and instructed not to work. Mandatory programs — like Social Security and Medicare — continue to operate, but some activities such as food safety inspections are halted.
The last government shutdown lasted from December 2018 through January 2019 and was the longest in history. During that time, national parks and monuments were closed; passport applications were delayed; some Small Business Administration loan programs weren’t dispensing money as usual; and other essential services were disrupted.
A federal shutdown can occur when Congress fails to pass a full-year spending bill or a stopgap CR by the end of the fiscal year on September 30. The departments and programs that lack approved annual funding — such as those involved in military activities, national security, the safety of human life and property, and tax collection — are shut down.
The courts and Congress are exempt from the shutdown, thanks to a decades-old Department of Justice opinion that they can continue performing their constitutional duties even when their appropriations bills lapse. However, many judicial and congressional employees are temporarily sent home during a shutdown. That’s also true for many other federal workers whose activities are deemed non-essential. Some workers, such as those who provide medical and social-services to the public, are kept on the job.