The partial US government shutdown entered a record 22nd day on Saturday (local time), as President Donald Trump remains steadfast in his demand for $7.8 billion to build a Mexico border wall and Democrats in Congress determined to refuse the funds.

The president issued a series of tweets in an effort to defend his stance and goad Democrats to return to Washington and end what he called “the massive humanitarian crisis at our Southern Border.”

“Democrats could solve the Shutdown in 15 minutes!” he said in one tweet, adding in another, “We will be out for a long time unless the Democrats come back from their ‘vacations’ and get back to work. I am in the White House ready to sign!”

But most politicians left town on Friday and will not return before Monday, leaving little chance for any solution to the stalemate before then.

The impasse has paralysed Washington. Its impact has been felt increasingly around the country with the president retaliating by refusing to sign off on budgets for swathes of government departments unrelated to the dispute.

As a result, 800,000 federal employees, including FBI agents, air traffic controllers and museum staff did not receive paychecks Friday.

The shutdown became the longest on record at midnight Friday, when it overtook a 21 day stretch in 1995-1996 under president Bill Clinton.

On Friday, however, Mr Trump backed off a series of previous threats to end the deadlock by declaring a national emergency and attempting to secure the funds without congressional approval.

“I’m not going to do it so fast,” he said at a White House meeting. Mr Trump described an emergency declaration as the “easy way out” and said Congress had to step up to the responsibility of approving the $7.8 billion he says is needed.

“If they can’t do it... I will declare a national emergency. I have the absolute right,” he said.

Until Friday, Mr Trump had suggested numerous times that he was getting closer to taking the controversial decision. One powerful Republican ally, Senator Lindsey Graham, tweeted after talks with Trump: “Mr President, Declare a national emergency NOW.” But the president himself acknowledged in the White House meeting that an attempt to claim emergency powers would likely end up in legal battles going all the way to the Supreme Court, as other Republicans and some of his advisers have reportedly cautioned him.

Opponents say that a unilateral presidential move would be constitutional overreach and set a dangerous precedent in similar controversies.

The standoff has turned into a test of political ego, particularly for Mr Trump, who came into office boasting of his deal-making powers and making an aggressive border policy the keystone of his nationalist agenda.

In two of his tweets Saturday, Trump pushed back on a media report that his White House was “chaotic” with no plan or strategy to end the shutdown.

“The Fakes always like talking Chaos, there is NONE...” he tweeted. “I do have a plan on the Shutdown.” “But to understand that plan you would have to understand the fact that I won the election, and I promised... a Wall at the Southern Border. Elections have consequences!”

Democrats, meanwhile, seem determined at all costs to prevent the president from getting the wall he has often promised in his campaign-style rallies.

Both Democrats and Republicans agree that the US-Mexican border presents major challenges, ranging from the violent Mexican drug trade to the plight of asylum seekers and poor migrants seeking new lives in the world’s richest country.

But Mr Trump has turned his single-minded push for more walls into a political crusade that opponents say is a stunt to stoke xenophobia in his right-wing voter base while wilfully ignoring the border’s complex realities.

For the president, who visited the Texas border with Mexico on Thursday, the border situation amounts to an invasion by criminals. Only in recent days has he begun describing the problem as “humanitarian.”

Some studies show that illegal immigrants generally commit fewer crimes than people born in the United States, although not everyone agrees on this.

More certain is that while narcotics do enter the country across remote sections of the border, most are sneaked through heavily guarded checkpoints in vehicles, the government’s own Drug Enforcement Administration said in a 2017 report.

Nancy Pelosi, the Democratic leader in the House of Representatives, said money should be spent on border security but not on walls.

“We need to look at the facts,” she said.

Separately, Puerto Rico’s governor urged Mr Trump to not redirect emergency funds from projects to help the storm-ravaged island to wall construction along the US-Mexico border.

Ricardo Rossello’s plea followed reports the White House has asked the Army Corps of Engineers to look into ways to divert funds destined for natural disaster relief for the wall.

In September 2017, Hurricane Maria tore through the US territory in the Caribbean, killing some 3,000 people, causing catastrophic material damage and crippling the island’s power grid.