President Trump agreed on Friday to reopen the federal government for three weeks while negotiations proceeded over how to secure the nation’s southwestern border, backing down after a month-long standoff failed to force Democrats to give him billions of dollars for his long-promised wall.

The decision paved the way for Congress to quickly pass spending bills that Trump would sign to restore normal operations at a series of federal agencies until February 15 and begin paying again the 800,000 federal workers who have been furloughed or forced to work for free for 35 days. He promised to ensure that workers quickly receive their back pay.

The surprise announcement was a remarkable comedown for a President who made the wall his non-negotiable condition for reopening the government.

But Trump relented as the effects of the shutdown rippled across the northeast, with effects far beyond pay cheques, such as air traffic slowing on Friday because of a shortage of air traffic controllers, who called in sick. With polls showing the President enduring most of the blame by the public, Republicans led by Senator Mitch McConnell of Kentucky, the majority leader, pressured Trump to agree to the temporary ceasefire.

Over the next three weeks, a committee representing both parties will negotiate a border security plan, but if it fails to reach a consensus, government agencies could close again.

The President’s concession came a day after two competing measures to reopen the government failed on the Senate floor. A Democratic bill, which would have reopened the government with no strings attached, received more votes than the bill backed by Trump, which included temporary protections for some undocumented immigrants in exchange for $5.7 billion for his proposed border wall.

McConnell spent part of Friday morning talking to Trump about what kind of border security the President would accept — other than a wall — in exchange for a promise from Democrats that they would at least debate the wall in the Senate during the regular course of business, according to a senior Republican aide familiar with the talks.

This person said that McConnell’s goal was to pressure moderate Democrats, who had expressed openness to a physical barrier, to agree to one. If they did not, the person said, Republicans or Trump could shut down the government again.