A government shutdown occurs when Congress cannot pass appropriations bills to fund federal agencies and programs, usually at the end of a fiscal year (March 14 this year). In that case, most of the government would shut down until the next funding measure is approved.
A shutdown affects many government services, though a few key activities remain in operation. In some cases, the activities are essential to national security or for the protection of lives and property. Examples include air traffic control, law enforcement and emergency medical care. In addition, services that are not subject to annual appropriations bills continue during a shutdown, such as Social Security checks and Medicare payments.
The government has extensive contingency plans that allow staff to remain on duty during a shutdown, but they may not work full time and have fewer resources at their disposal. This leads to things like delayed processing of passport applications, denied Small Business Administration loans and slowed food-safety inspections. The shutdown also impacts visitors at national parks and the employees of the U.S. Postal Service.
Over two million people across the country work for the federal government and lose their paychecks during a shutdown. These workers are generally considered “essential” and therefore will continue to work without pay until the shutdown ends. In contrast, workers who are not “essential” are furloughed and stay home. Congressional aides and some administrative staff are also affected by a shutdown. In addition, the issuance of proposed and final rules could be delayed during a shutdown.