Friday evening, the US House of Representatives adjourned without Congress having approved funding for the federal government to continue functioning, meaning that at midnight, federal agencies will begin to shut down.

With the federal government shut down, government employees will face furloughs and delayed payments for work as the bureaucracy slowly grinds to a halt. The basic functions of government, such as air traffic controllers, the Secret Service, diplomats and the Post Service, but nonessential functions such as the Internal Revenue Service, national libraries, forests and parks, and the space agency NASA would heavily furlough their workforces.

About 420,000 federal workers would continue to work with delayed pay — getting their checks whenever Congress does reauthorize funding — but another 380,000 would be furloughed, meaning they'd be given time off without pay, ABC noted.

Spending bills authorizing the continued funding of the departments of defense, labor, education and health and human services have already been signed, so those areas are unaffected. Lawmakers have also cleared bills funding the legislative branch, military construction, veterans affairs and energy and water development, ABC noted.

The impending shutdown was the focus of a deep-seated battle between US President Donald Trump and congressional Democrats over the issue of funding his pet project, the border wall with Mexico. Trump made clear he would okay no funding bill without a deal for money for $5.7 billion in wall funding.

A House bill on Thursday actually did provide such funding, but the Senate failed to pass the bill. While Trump urged Senate Republican leaders to invoke the so-called "nuclear option" and reduce the number of necessary votes for the bill to pass from 60 votes to a mere 51 — stifling the ability of Democrats in opposition to block the bill — that wasn't an option Senate Majority Leader Mitch McConnell chose to invoke Friday.

Some of the many Bills that I am signing in the Oval Office right now. Cancelled my trip on Air Force One to Florida while we wait to see if the Democrats will help us to protect America’s Southern Border! pic.twitter.com/ws6LYhKcKl — Donald J. Trump (@realDonaldTrump) December 21, 2018

​The House is set to return from recess at noon on Saturday, meaning the shutdown may be temporary if a deal can still be reached. However, Trump has warned that if Democrats continue to oppose border wall funding, "there will be a shutdown that will last for a very long time."