The last shutdown was also the longest in US history, lasting 35 days from December 22, 2018, to January 25, 2019, when Trump announced he had reached a tentative deal with congressional leaders to reopen the government for three weeks while negotiations on the border wall continued.

In the last 50 years the federal government has come to at least a partial shutdown 11 times. Some have lasted a day or more. Others have stretched into weeks.

The 1977 shutdown, which held the record for the longest in U.S. history for just 12 months, was sparked by disagreements over whether Medicaid should fund abortion care. Democrats held majorities in both chambers of Congress.

When the Trump administration decides it can spend money from any budget account on anything it wants and not spend appropriated funding, there are no limits to the president's budgetary powers.

A shortage of air traffic controllers may have played a role in ending the last government shutdown in 2019. U.S airlines are once again bracing for possible delays in commercial aviation.