Appropriations
The annual laws that give federal agencies legal authority to spend money.
Authorising a program and funding it are two separate acts of Congress. An authorisation says a program may exist and sets its terms; an appropriation provides the budget authority to actually spend on it.
The appropriations process is handled by the Appropriations Committees in each chamber, divided into twelve subcommittees whose jurisdictions map to the twelve regular bills. Mandatory spending — Social Security, Medicare, interest on the debt — flows from permanent law and is not part of this annual process, which is why the annual fight covers a minority of total federal spending.
A worked example
Suppose Congress authorises a research programme “at such sums as may be necessary” for five years. That authorisation, on its own, moves no money. The programme spends only what an appropriations act provides each year — and that figure can be smaller than the authorised ceiling, or zero. In a year when the relevant bill is not enacted by 1 October, the programme’s spending authority lapses until a continuing resolution or a full-year act restores it.
The twelve bills are organised by agency cluster, not by policy: Defense; Labor-HHS-Education; Homeland Security; and so on. A single programme can depend on one bill while the department that runs it draws on another.
How to read it in coverage
“Congress approved $X for Y” usually means an appropriation; “Congress authorised Y” usually means the programme now exists on paper. The two are routinely conflated. When a story says a programme was “defunded”, check whether the authorisation was repealed or whether the appropriation was simply not made this year — they are different things, and the second is reversible in the next bill.
Twelve regular appropriations bills fund the discretionary side of the government each year. Without one — or a continuing resolution — an agency cannot obligate funds.