The longest government shutdown in United States history occurred between December 22, 2018, and January 25, 2019. It was the byproduct of a dispute over border wall funding, a central issue of President Donald Trump's administration.
The president demanded more than $5 billion to fund the construction of a wall along the U.S.-Mexico border — a promise he'd made to his supporters while campaigning for the White House.
House Democrats, led by the speaker of the House Nancy Pelosi, and Senate Democrats, however, refused to approve the necessary funding bills. This stalemate led to a funding gap that affected approximately 800,000 federal workers and multiple federal agencies.
The shutdown ended after 35 days, when President Trump agreed to reopen the government for three weeks to allow for negotiations on border wall funding. On February 15 the shutdown would have resumed, but the president announced he had signed a spending bill that allowed the federal government to remain open.
The bill included $1.4 billion for border fencing; however, this funding was well below the $5.7 billion President Trump wanted. This led the president to declare a national emergency in an attempt to bypass Congress and access funds for the border wall, a move that was fraught with legal challenges (such as lawsuits from states over potentially lost federal funds) and ignited a national debate.
Ultimately, the 2018-2019 shutdown had widespread effects, halting many government operations and services across the country. This had negative consequences for federal employees, the American public, Native Americans and members of the Coast Guard.
According to the Congressional Budget Office, the shutdown cost the federal government at least $5 billion. This includes $3 billion in back pay to all the furloughed workers and $2 billion in lost tax revenue (since the Internal Revenue Service was not able to conduct all of its usual compliance checks).