Congress funds government operations through an annual appropriations process. However, Congress routinely misses the Oct. 1 deadline (the first day of the new fiscal year) for enacting appropriations bills.
When some or all of the appropriations bills have not been enacted by then, Congress passes continuing resolutions to prevent a government shutdown. Temporary continuing resolutions allow departments and agencies to continue operations, generally at existing funding levels, while Congress continues work on a final appropriations bill. Congress may ultimately choose to skip a regular appropriations bill altogether, in which case funding can be provided through the end of the fiscal year with a full-year continuing resolution.
During the FY 2010 budget process, Congress passed several continuing resolutions. The last appropriations bill was not signed into law until Dec. 19, 2009.