US government shutdowns happen when Congress fails to pass funding laws. Every year, Congress must approve 12 appropriation bills or a short-term stopgap called a continuing resolution before the fiscal year starts on October 1. Without either, a funding gap forces parts of the government to shut down.This time, Congress passed a continuing resolution signed on September 2, 2026, funding the government through December 11. The next showdown arrives when that deadline hits. Last year saw a record 43-day shutdown, and watchers expect December to bring tense negotiations again.During a shutdown, agencies furlough workers deemed non-essential. Essential staff such as active-duty military, air traffic controllers and law enforcement keep working, often without pay until funding returns. National parks and federal museums close or run with reduced staff. Passport and visa processing slows.Social Security and Medicare payments generally continue because they come from mandatory spending, not annual appropriations. But nutrition assistance, housing vouchers and federal loans can face delays. The Congressional Budget Office has estimated shutdowns cost hundreds of millions of dollars a day in lost compensation.