What causes a federal shutdown?
Congress provides most discretionary funding through 12 regular appropriations bills. If funding for an agency expires before a new appropriation becomes law, the Antideficiency Act generally bars the agency from incurring new obligations. The agency then follows its contingency plan for an orderly shutdown.
What work can continue?
Activities may continue when their funding has not lapsed or when the law allows an exception. Common categories include work necessary to protect human life or federal property, functions tied to constitutional duties, and activities funded by fees or permanent appropriations.
“Essential employee” is common shorthand. Official guidance usually uses excepted for employees who may keep working despite a lapse and exempt for work supported by funding that has not lapsed.
Who decides what closes?
The legal framework is government-wide, but each agency applies it to its own programs. Agency contingency plans estimate which employees will be retained and describe which services may pause. Those plans can change with the scope and duration of a particular lapse.
How does a shutdown end?
The House and Senate must pass the same funding text. The President then signs it, allows it to become law without a signature, or Congress overrides a veto. Agencies can reopen after legal spending authority returns.
Do federal employees receive back pay?
Yes. The Government Employee Fair Treatment Act of 2019 requires retroactive pay for affected federal employees after a lapse ends. The timing of the payment can vary by payroll cycle. Contractor employees do not have the same automatic statutory protection.
Partial vs. full shutdowns
Congress funds most discretionary programs through 12 annual bills. If some of those bills are already law, only the unfunded agencies lapse. That is a partial shutdown, and it can look nothing like a government-wide lapse. The 2026 DHS-only shutdown is the recent example.
Go deeper
See federal employee pay and furlough rules, compare past shutdowns, or search a specific program in the impact checker.