Almost 800,000 federal employees – including 95 per cent of NASA – will have their pay cheques cancelled over the Christmas period because Donald Trump hasn’t got his wall.

More than half of those employees are deemed to be essential workers – border security workers at airports, for example – and will be forced to work without pay during the third government shutdown this year. For how long?

Perhaps for as long as it suits the president’s need to be at the centre of things – and serves to distract even the media from his legal nightmares.

He has in fact promised to let it drag out, tweeting as follows: “The Democrats, whose votes we need in the Senate, will probably vote against Border Security and the Wall even though they know it is DESPERATELY NEEDED. If the Dems vote no, there will be a shutdown that will last for a very long time. People don’t want Open Borders and Crime!”

The Democrats, whose votes we need in the Senate, will probably vote against Border Security and the Wall even though they know it is DESPERATELY NEEDED. If the Dems vote no, there will be a shutdown that will last for a very long time. People don’t want Open Borders and Crime!

— Donald J. Trump (@realDonaldTrump) December 21, 2018

About 380,000 public servants in non-essential roles affected by the shutdown – including park rangers and public housing workers – will be sent home on unpaid leave to twiddle their thumbs.

In previous shutdowns, although there is no formal provision for back-pay, workers have eventually been compensated.

The shutdown has occurred because Congress won’t approve $US5 billion ($7.1 billion) in funding for the President’s signature border wall with Mexico, Democrats say it’s not necessary, it won’t work and is a waste of public funds.

Congress had already approved a spending package that will pay for 75 per cent of the federal government juggernaut, including defence, the postal service, social security and human services.

The Democrats now own the shutdown!

— Donald J. Trump (@realDonaldTrump) December 21, 2018

The departments of Transportation, Housing and Urban Development, State, Interior, Agriculture, Treasury, Commerce, Homeland Security and Justice, plus other agencies, were operating under what is called a continuing resolution set to expire at midnight, Washington time.

Their workers will face an uncertain Christmas, with a potential speed bump for the US economy. Research found that in previous shutdowns, furloughed workers and their families – even those with money in the back – simply stop spending.

So that’s the human cost of the shutdown that Mr Trump is willing to see drag on for a long time – and blame it on the Democrats.

It’s all about Donald Trump

The real story, of course, is Mr Trump himself – and what is perceived to be his final flight from political sanity.

For the President, the shutdown is just one more piece of ratbaggery in a week where he cut ties to even his greatest assets, and is seemingly ready to go to the mattresses with his red-cap base of supporters.

This was the week where he unilaterally announced that all US troops in Syria would be pulled out immediately – against all advice, and with much condemnation from his most fevered supporters, the hosts of Fox and Friends.

No matter, Mr Trump says the troops will be pulled out and a celebration should be had – not for the mysterious world-saving birth of Christ, but for a total victory over Islamic State that no one else on the planet was aware of.

A day after the announcement, the only adult left in the administration, US Defence Secretary James Mattis, resigned citing policy differences. That alone was cause for disquiet, but for Mr Trump, it means he is finally unshackled from listening to anybody but his own instincts.

This week’s departure of James Mattis was a massive blow to the Trump administration. Photo: Getty

What’s really going on here?

The punditry believes the chaos is Mr Trump’s response to losing the House to the Democrats in the mid-term elections – and the threat they pose to his agenda – not to mention tenure.

As The New York Times proffered: “If there was a common thread in President Trump’s actions this week, it was his unswerving conviction that his political survival depends on securing his conservative base.”

Bringing the troops home, more broadly withdrawing the US from global concerns, and securing the wall were his core campaign pledges.

The New Yorker sort of agrees with the Times, but put more focus on Mr Trump’s personal need for attention: “In geo-strategic terms, announcing just before Christmas the withdrawal of US troops from Syria was a boon for Damascus, Ankara and Moscow. Politically, it was a stunt designed to garner attention and please the base.”

What’s largely gone unremarked is that suddenly, for a few days, Mr Trump’s mounting legals woes have hardly been mentioned.

Last week, they were full throttle.

And so, for the moment, perhaps for the weeks ahead – for what could be a long and painful standoff for those unpaid public servants – Mr Trump has given his enemies something else to talk about.

As for the legion of great-again wall enthusiasts – harbouring so many grievances as they do – Mr Trump is allowing them to wallow for a while in the crazy idea that they really do matter.