This would mark the first special session since 1948, when President Harry Truman called on Republicans to reconvene for discussions on health care, civil rights, and Social Security matters.

Trump this week restored pay for Transportation Security Administration workers via executive order, though it’s unclear how sustainable that workaround is to resolve travel chaos that saw passengers across the country waiting in line at checkpoints for several hours or more.

White House press secretary Karoline Leavitt said at a Monday briefing that “nothing will be truly normal again until Democrats do the right thing to fund this agency fully.”

DHS includes a broad spectrum of sub-agencies including the Federal Emergency Management against and US Customs and Border Protection and US Immigration and Customs Enforcement.

The shutdown began with Senate Democrats demanding changes to Trump’s campaign to mass-deport illegal immigrants. Republicans have since opposed measures to fund only part of the department while setting aside immigration enforcement for further debate.

Presidents have used their constitutional power to force a special session just 27 times. Before Trump, the most recent instance was in 1856 before the Civil War.