Large swaths of the U.S. government could temporarily close at midnight on Friday if Congress does not approve a stopgap spending bill due to pressure from Donald Trump.

GOP Representatives are scrambling to pass a funding agreement to avoid a government shutdown. These agencies would be impacted.

When would a federal shutdown start? Which parts of the government would shut down? Will payments to Social Security recipients be affected?

A bipartisan deal to avert a government shutdown over the holidays collapsed Dec. 18 after President-elect Donald Trump issued new demands, including that Congress raise the debt ceiling to extend funding.

As many Americans begin their holiday festivities, service members are facing uncertainties as a potential government shutdown looms.

Federal government shutdowns can be disruptive, with thousands of workers furloughed and most of them not getting paid on time. Taxpayers won’t get calls returned, there may be longer lines at airports during one of the busiest travel weeks of the year and many national parks will close.

A shutdown furloughing hundreds of thousands of federal workers would restrict a wide range of government operations, although critical services would continue.