The US government shutdown is now the longest such closure in history. On Sunday, day 23, members of Congress were out of Washington, Donald Trump was unmoved in the White House, his border wall unbuilt, and around 800,000 federal workers were still without pay and facing mounting hardship.

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From a White House he described as empty, Trump complained on Twitter about multiple reports in the press that his administration is in chaos, lacking a plan to end the impasse.

“I do have a plan on the Shutdown,” Trump wrote. “But to understand that plan you would have to understand the fact that I won the election, and I promised safety and security for the American people. Part of that promise was a Wall at the Southern Border. Elections have consequences!”

Trump added: “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!”

Trump has however repeatedly pledged to veto legislation initially supported by both parties to reopen the government, without funding for his wall.

Friday was the first payday of the year for federal workers and contractors affected by the closure, some at home, some forced to work. Some paychecks turned up blank. Contractors may not recoup lost earnings. As callouts rose among workers deemed essential, so did problems for government programmes, for courts, national parks and vital transport and infrastructure services including major airports.

Even White House staffing is severely affected, prompting Trump to complain in a tweet: “There’s almost nobody in the WH but me.”

We will be out for a long time unless the Democrats come back from their ‘vacations’ and get back to work Donald Trump

On Saturday the shutdown passed the 21-day mark set when Bill Clinton faced a Republican Congress in 1995 and 1996. Nine of 15 cabinet-level departments were not funded. Earlier, Trump backed away from threats to declare a national emergency and build the wall with money appropriated from military, water management and disaster management funds, among other sources.

“We want Congress to do its job,” the president said in a discussion on border security at the White House. “What we’re not looking to do right now is national emergency.”

Nonetheless, Trump insisted he had the right to declare an emergency if he chose to, and continued to insist there was a crisis at the border.

“Other presidents have called national emergencies for lesser importance than this,” he told Fox News in an interview on Saturday night.

Democrats reject Trump’s insistence there is a crisis and continue to prepare a response to an emergency declaration that would involve recourse to the courts.

The impasse is over the $5.7bn needed for a wall on the border with Mexico that Trump promised on the campaign trail, saying Mexico would pay for it. Democrats who control the House are determined not to give it to him, whether or not – and most analysts say not – he is correct that savings from a new trade deal will mean Mexico pays after all.

The White House has suggested building the wall with steel rather than concrete as a key concession.

“This is where I ask the Democrats to come back to Washington and vote for money for the wall, the barrier,” Trump said on Friday. “Whatever you want to call it, it’s OK with me. They can name it whatever, they can name it peaches.”

Play Video 1:24 Donald Trump backs away from declaring national emergency over border wall – video

Democrats, who oppose any wall as a matter of principle, are not buying that. They point to polling that indicates support for their opposition to Trump on the wall and other immigration matters, and to remarks by Trump in December in which he said he would be proud to force a shutdown.

In a statement on Saturday, the Connecticut Democratic senator Chris Murphy said “this was already the dumbest shutdown ever”.

“The only reason we are shut down is that President Trump wants it that way,” he said. “Let’s be very clear about how we got here. Back in December, the White House endorsed a bipartisan deal that passed the Senate with unanimous support – and then Republicans changed their mind.”

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Republicans who control the Senate will not pass legislation to reopen parts of government advanced by Democrats in the House, knowing Trump will not sign it, but feel relatively sheltered from blame thanks to the president’s intransigence. Majority leader Mitch McConnell has maintained a studious if increasingly controversial silence.

Some moderate Republicans have seemed to waver. Trump has not. But as he remains in the White House, after a short visit to the border this week, the pressure is rising: not only from the shutdown but also from continued revelations in the special counsel’s Russia inquiry and as House committees prepare to investigate his actions.

According to S&P Global Ratings, meanwhile, the shutdown has cost the US economy $3.6bn, a toll that will exceed Trump’s funding demand in two weeks’ time.

The National Weather Service is among government agencies affected by the shutdown. But enough forecasters remain on duty to say that the capital is about to be hit by a major snowstorm. Members of Congress were sure to leave town to avoid it.