Trump -- a self-styled master dealmaker -- hit two top Democrats as weak on crime, immigration and the economy, hours before sitting down with them in Congress.
"Meeting with 'Chuck and Nancy' today about keeping government open and working," Trump tweeted.
"Problem is they want illegal immigrants flooding into our Country unchecked, are weak on Crime and want to substantially RAISE Taxes. I don't see a deal!"
Behind the tough talk, Trump needs Democratic leaders Chuck Schumer in the Sentate and Nancy Pelosi in the House to rally their party's votes to keep the government running through the next 10 months.
In 2013, a similar spending feud caused 850,000 thousand government officials to be sent home temporarily.
National parks closed for two weeks and as much as half a percentage point was shaved off economic growth.
Trump has staked much of his fragile political reputation on being a dealmaker and a good steward of the economy, so failure could be damaging.
But Democrats are demanding a steep political price for their support.
They say funding for Trump's border "wall" must be stripped out and Trump must honor the Obama administration's pledge to allow migrants brought to the United States as kids to remain here.
The issue, as tricky is it is, is not the only problem on Trump's plate.
- Tough sledding -
The president went back to work Monday at a festively decorated White House, with a formidable to-do list that will decide whether his Christmas is filled with political misery or cheer.
After spending much of November in East Asia and Florida, Trump returned to marbled corridors bedecked with garlands and graced by ballerinas but also chilled by the prospect of a daunting few weeks ahead.
December also sees a "debt ceiling" deadline that, if missed, could see the US government hurtle towards a technical default in the new year.
The legislative wrangling comes against the backdrop of a fiercely contested December 12 election in Alabama, which will be a bellwether for Trump's support and could tilt control of the Senate away from Republicans.
Republican officials admit that controversies may split right wing voters, handing a rare victory to Democrats in that deeply Republican state.
Trump has thrown his weight behind party candidate Roy Moore, who has refused to withdraw despite a string of allegations that he molested or sexually assaulted teenage girls when he was in his 30s.
The White House says Trump will not campaign with Moore, but he has questioned the allegations and urged voters to oppose the Democrat candidate, Doug Jones.
But some Republicans plan to vote for a "write-in candidate" whose name is not on the ballot.
- Death or taxes -
Even before the election, before the spending fight and another battle over the debt ceiling, Trump's primary task will be to pass tax cuts, which Republicans see as absolutely vital to keep voters and donors happy.
With the party in control of the White House and both chambers of Congress, the task should be straightforward. But little is straightforward in Washington these days.
The administration's chief salesmen, Treasury Secretary Steve Mnuchin and top economic aide Gary Cohn -- both multimillionaires -- have struggled to convince the public that the tax cut will help middle class families, as Trump insists.
With the details still being thrashed out, a Harvard-Harris Poll showed a majority of voters opposed the bill, believing it will hurt them financially.
Democrats have been busy trying to portray the proposals as good for big business but bad for ordinary Americans.
The non-partisan Tax Policy Center estimates nine percent of taxpayers would pay more in 2019, rising to 50 percent by 2027.
Half a dozen Republican senators have publicly expressed doubts about the tax cut plan. The House has already passed its own version.
Some are concerned that the proposals would increase the national debt by around $1.4 trillion by 2027, according to the non-partisan Congressional Budget Office.
The White House argues that the cuts will boost growth and this in turn will increase tax revenue, although most economists disagree.
With the slightest of Senate majorities, Trump cannot lose more than two Republican votes.
"Every single member of the Republican conference is working to get to yes," said number two Senate Republican John Cornyn.
Having so far failed to pass health care, immigration or infrastructure reforms, he faces a party revolt if he cannot make tax cuts law.
Top Republican Paul Ryan said the country was at "a generational defining moment."
Trump will travel to Missouri on Wednesday to make the case, and to heap pressure on Democratic Senator Claire McCaskill who faces a tough reelection fight.