From December 22, 2018, until January 25, 2019, the United States federal government entered a shutdown. It was the second and final federal government shutdown involving furloughs during the first presidency of Donald Trump. It occurred when the 115th Congress and Trump could not agree on an appropriations bill to fund the operations of the federal government for the 2019 fiscal year, or a temporary continuing resolution that could extend the deadline for passing a bill. The Antideficiency Act prohibits federal departments or agencies from conducting non-essential operations without appropriations legislation in place. As a result, nine executive departments with around 800,000 employees had to shut down partially or in full, affecting about a quarter of government activities and causing employees to be furloughed or required to work without being paid. The Congressional Budget Office estimated the shutdown cost the American economy at least $11 billion USD, excluding indirect costs that were difficult to quantify.

The shutdown stemmed from an impasse over Trump's demand for $5.7 billion in federal funds for a U.S.–Mexico border wall. In December 2018, the Senate unanimously passed an appropriations bill without wall funding, and the bill appeared likely to be approved by the Republican-controlled House of Representatives and Trump. After Trump faced heavy criticism from some right-wing media outlets and pundits for appearing to back down on his campaign promise to "build the wall", he announced that he would not sign any appropriations bill that did not fund its construction. As a result, the House passed a stopgap bill with funding for the wall, but it was blocked in the Senate by the threat of a Democratic filibuster.

In January 2019, representatives elected in the November 2018 election took office, giving the Democrats a majority in the House. The House immediately voted to approve the appropriations bill that had previously passed the Senate unanimously and included no funding for the wall. For several weeks, Trump maintained that he would veto any bill that did not fund an entire border wall, and Republican Senate majority leader Mitch McConnell blocked the Senate from considering any appropriations legislation that Trump would not support, including the bill that had previously passed. Democrats and some Republicans opposed the shutdown and passed multiple bills to reopen the government, arguing that the government shutdown amounted to taking civil servants "hostage" and that negotiations could only begin once the government was reopened.

On January 25, 2019, Trump endorsed a stopgap bill to reopen the government until February 15 to allow for negotiations to take place on an appropriations bill. However, he reiterated his demand for border wall funding and said that he would shut down the government again or declare a national emergency and use military funding to build the wall if Congress did not appropriate the funds by February 15. With a veto-proof majority, both houses of Congress passed an appropriations bill on February 14 that included $1.375 billion for 55 miles of steel fencing along the border. The following day, Trump declared a national emergency to fund the wall, after being unsatisfied with the funding in the appropriations bill.

The end of the shutdown on January 25 occurred several hours after the Federal Aviation Administration was forced to limit flights at several major airports due to a high incidence of sick leave taken by air traffic controllers, who had been required to work during the shutdown without receiving paychecks. Though never claimed as a strike action, the development was widely credited as precipitating the shutdown's end.

Trump's approval rating dropped during the shutdown. A majority of Americans opposed exploitation of the shutdown as a negotiating strategy and held Trump responsible for the shutdown: A CBS News poll found that 71% of Americans considered the border wall "not worth the shutdown" and a Washington Post/ABC News poll found that 53% of Americans blamed Trump and Republicans for the shutdown, compared to 34% who blamed Democrats and 10% who blamed both parties.

Background During his 2016 campaign, then-candidate Trump promised to build a wall along the Mexico–United States border for which Mexico would pay. The president of Mexico rejected the idea of providing any funding for a U.S. border wall. In 2018, Trump requested $ in federal funding for some of barrier on the border, mostly to replace of aging fence built under the Secure Fence Act of 2006. On December 25, 2018, Trump reversed course, suggesting that he might accept of either mostly refurbished barrier (rather than new barriers in locations that did not previously have them) by November 2020. Trump's proposals and public statements on the wall have shifted widely over time, with varied proposals as to the design, material, length, height, and width of a wall.

In September 2018, Congress passed two "minibus" appropriations bills for the 2019 United States federal budget, which began on October 1, 2018. These bills combined five of the 12 regular appropriations bills covering 77% of federal discretionary funding, and included a continuing resolution until December 7 for the remaining agencies. On December 6, Congress passed a second continuing resolution to December 21, to give more time for negotiations on Trump's proposed border wall, which had been delayed due to the funeral of George H. W. Bush.

A Senate Homeland Security appropriations bill, negotiated by both parties and reported by the committee to the Senate, provided for $ for border security, including funds for "approximately 65 miles of pedestrian fencing along the southwest border in the Rio Grande Valley Sector". The bill did not receive a vote on the Senate floor, although House Democratic Whip Steny Hoyer indicated that such a proposal could be acceptable to House Democrats. Senate Minority Leader Chuck Schumer (D-NY) said the Democratic Party would not support $ for the border wall. At a press conference before the government shutdown, he noted "the $1.6 billion for border security negotiated by Democrats and Republicans is our position. We believe that is the right way to go."

Beginning of shutdown

On December 11, President Trump held a televised meeting with Speaker-designate Nancy Pelosi and Senate Minority Leader Chuck Schumer in the Oval Office and asked them to support an appropriation of $5.7 billion for funding of a border wall along the U.S. southern border with Mexico. They refused, resulting in an argument between Trump and both Congressional leaders. During the contentious discussion, Trump remarked, "I am proud to shut down the government for border security ... I will be the one to shut [the government] down. I'm not going to blame you for it ... I will take the mantle. I will be the one to shut it down." Schumer replied, "We shouldn't shut down the government over a dispute." Ten days later, Trump blamed Democrats for the impending shutdown.

Three days later, Politico reported that Trump was willing to sign a bill with no funding for a border wall that delayed a government shutdown into 2019 and the new Congress. On December 18, following a meeting with Trump, Senate Majority Leader Mitch McConnell said that the government would not shut down on December 22 and that Trump was "flexible" over funding for a border wall. Senate Appropriations Committee Chairman Richard Shelby commented that the most likely resolution was a bill that funded the government until early February. Schumer added that his caucus would "very seriously" consider such a bill and Senate Majority Whip John Cornyn said "I don't know anybody on the Hill that wants a shutdown, and I think all the president's advisers are telling him this would not be good."

On December 19, the Senate passed a second continuing resolution () that would fund the government until February 8, 2019. Pelosi announced that House Democrats would support the measure, meaning it would overcome opposition from conservative Republicans and pass the House. On December 20, following increased criticism from conservative media, pundits, and political figures, Trump reversed his position and declared that he would not sign any funding bill that did not include border wall funding. The same day, the House passed a continuing resolution that included $5 billion for the wall and $8 billion in disaster aid. This bill failed in the Senate. Trump's changing position caused consternation among Senate Republicans.

Shutdown The shutdown started December 22 and Trump announced that he would cancel his planned trip to Mar-a-Lago for Christmas and stay in Washington, D.C. The meaning of the term "wall" was expected to be an aspect of the negotiations.

Legislation 115th Congress Congress adjourned on December 22 for the Christmas and holiday season, with many predicting that the shutdown would not be resolved until the start of the 116th Congress. The Senate reconvened on December 27 for four minutes, with Senator Pat Roberts (R-KS) presiding over the session. The House briefly reconvened as well, with Majority Whip Steve Scalise (R-LA) saying that members should not expect any further votes for the rest of 2018. Representative Jim McGovern (D-MA) went to the House floor to try to force consideration of a short-term funding bill to end the shutdown that the Senate had already passed, but the Republican Speaker-pro-tem refused to let him speak.

Congress then adjourned again until December 31, 2018, for a pro forma session. On January 2, 2019, the last full day of the 115th Congress, there was a pro forma session scheduled to last several minutes.

116th Congress House The new Congress was sworn in on January 3, 2019, and one of the first orders of business in the House after electing the Speaker and swearing in the new members was a continuing resolution to fund the Department of Homeland Security until February 8 (), which passed by a vote of 239–192; and a package combining five appropriation bills funding the rest of the government for the remainder of the fiscal year (), passed by a vote of 242–189. The bills contained $1.3 billion of funding for border security, but no additional funding for a border wall.

Beginning on January 9, the Democratic-controlled House voted on four appropriations bills individually:

Financial Services and General Government Appropriations Act, 2019 () – bill to restore appropriations to the Treasury (including the Internal Revenue Service), federal judiciary, District of Columbia, and a number of independent agencies, including the Federal Communications Commission, Federal Trade Commission, General Services Administration, and Securities and Exchange Commission. The House passed the legislation on January 9, on a 240–188 vote, with every Democrat and eight Republicans voting yes, and all other Republicans voting no.Ashley Killough & Clare Foran, House passes bill to reopen IRS and other financial agencies, despite veto threat , CNN (January 1, 2009).The Latest: House passes bill to fund agencies amid shutdown , Associated Press (January 9, 2019).Final Vote Results for Roll Call 21 , Office of the Clerk, United States House of Representatives (January 9, 2019). Agriculture, Rural Development, Food and Drug Administration, and Related Agencies Appropriations Act, 2019 () – bill to restore appropriations to the Department of Agriculture (including food stamps), the Food and Drug Administration, and related entities. On January 10, the House passed this bill 243–183.Ashley Killough, House passes bills to reopen Agriculture, Transportation departments , CNN (January 10, 2019).Lindsey McPherson, Republican defections on House spending bills to end shutdown tick up , Roll Call (January 10, 2019).