A government shutdown has begun in the US after the Senate rejected a short-term spending measure that would have kept federal funds flowing until November 21.
Democrats had been leveraging the possibility of a shutdown in an attempt to negotiate an extension to healthcare benefits, but the Republicans were not willing to compromise.
It is the first government shutdown in more than six years.
When a lapse in funding occurs, government departments are required to cease activity and furlough "non-excepted" employees.
At issue on the government funding front is $US1.7 trillion ($2.58 trillion) for agency operations, which amounts to roughly one-quarter of the government's total $US7 trillion ($10.6 trillion) budget.
Much of the remainder goes to health and retirement programs and interest payments on the growing $US37.5 trillion ($57 trillion) debt.
This is the 15th government shutdown since 1981.
The longest government shutdown in US history stretched over 35 days during December 2018 and January 2019 during Mr Trump's first term in office, in a dispute over border security.
Independent analysts warn the shutdown could last longer than past closures, with Mr Trump and White House officials threatening to punish Democrats with permanent cuts to government programs and the federal payroll.
Mr Trump's campaign to radically reshape the federal government is already on track to push out some 300,000 workers by December.
Rising tensions between major parties
Senate Democratic leader Chuck Schumer said in a floor speech: "All they want to do is try to bully us. And they're not going to succeed”.
Before the shutdown, Mr Trump shared a deepfake video showing manipulated images of Mr Schumer appearing to criticise Democrats while top House Democrat Hakeem Jeffries stood next to him, with a crudely drawn sombrero and moustache imposed over his face.
"It was childish. It was petty," Mr Schumer told reporters.
"It's something that a five-year-old would do, not a president of the United States. But it shows how unserious they are. They don't give a damn about the harm they will cause with their shutdown".
Republican Senate Majority Leader, John Thune, described the failed short-term spending bill as a "non-partisan" measure, devoid of partisan policy riders, that Democrats have had no problem accepting in years past.
"What's changed is, President Trump is in the White House. That's what this is about. This is politics. And there isn't any substantive reason why there ought to be a government shutdown," Mr Thune told reporters.
The Republicans hold majorities in both chambers of Congress.
But legislative rules require 60 of the 100 senators to agree on spending legislation, meaning at least seven Democrats are needed to pass a funding bill.
Increased polarisation in US politics
University of Chicago professor Robert Pape said the unusually polarised US political climate — in the aftermath of Charlie Kirk's assassination and the growing power on the extreme wings of both parties — could make it harder for party leaders to agree on a deal to reopen the government.
Democrats are under pressure from their frustrated supporters to score a rare victory ahead of the 2026 midterm elections that will determine control of Congress for the final two years of Mr Trump's term.
The healthcare push has given them a chance to unite behind an issue that resonates with voters.
Along with the extended health subsidies, Democrats have also sought to ensure that Mr Trump will not be able to undo those changes if they are signed into law.
Mr Trump has refused to spend billions of dollars approved by Congress, prompting some Democrats to question why they should vote for any spending legislation at all.
University of Chicago political science professor, Robert Pape, says a deeply-divided US is entering into unchartered territory.
"The rules of politics are radically changing and we can't know for sure where all of this is going to end," he said.
"Each side would have to backtrack against tens of millions of truly aggressive supporters, their own constituents, which is going to be really hard for them to do."
Reuters/ABC
