WASHINGTON — The White House on Sunday pushed the federal government closer to the brink of a partial shutdown later this week, digging in on its demand for $5 billion to build a border wall as congressional Democrats stood firm against it.

"We're going to do whatever is necessary to build the border wall to stop this ongoing crisis of illegal immigration," said White House senior adviser Stephen Miller.

Asked if that meant having a government shutdown, he said: "If it comes to it, absolutely."

But the president doesn't have the votes from the Republican-controlled Congress to support funding for the wall at that level.

Democratic congressional leaders, Sen. Chuck Schumer and Rep. Nancy Pelosi, have proposed no more than $1.6 billion, as outlined in a bipartisan Senate bill. The money would not go for the wall but for fencing upgrades and other border security. Democrats also offered to simply keep funding at its current level, $1.3 billion.

Trump said last week he would be "proud" to have a shutdown to get Congress to approve a $5 billion down payment to fulfill his campaign promise to build a wall on the U.S.-Mexico border. “I will take the mantle of shutting it down,” said Trump during the now infamous meeting between him, Nancy Pelosi, and Chuck Schumer. “I’m going to shut it down for border security.”

“My friends on the other side of the aisle know the President’s wall is wrong and ineffective and that it cannot pass,” said Schumer during a floor speech in the Senate on Monday. “The President’s daily Twitter outbursts cannot alter that reality.”

About one-quarter of the government would be affected, including the departments of Homeland Security, Transportation, Agriculture, State and Justice, as well as national parks.

"He is not going to get the wall in any form," Schumer said.

Both parties in Congress have suggested that Trump would likely need to make the next move to resolve the impasse. The House is taking an extended weekend break, returning Wednesday night. The Senate returns Monday after a three-day absence.

Trump had neither accepted nor rejected the Democrats' proposal as of Friday, according to the Democrats, telling them he would take a look. Trump will need Democratic votes either way, now or in the new year, for passage.

“Usually the game in this process is that everyone is shutting down the Government and they’re sitting there completely innocent,” said Professor David Super of Georgetown University’s School of Law. “It is in some respects refreshing that the President admits to what he’s doing.”

Schumer declined to say whether Democrats would be willing to consider proposals other than the two options that he and Pelosi offered.

Republicans "should join us in one of these two proposals, which would get more than enough votes passed and avoid a shutdown," Schumer said. "Then, if the president wants to debate the wall next year, he can. I don't think he'll get it. But he shouldn't use innocent workers as hostage for his temper tantrum."

The consequences of a shut down could be severe. Several Federal agencies ranging from the USDA to the Department of Homeland Security could be affected if funding isn’t approved by midnight on Friday.

Emergency management personnel and other ‘essential employees’ would continue to work with the expectation that Congress would award back-pay pending the conclusion of the shutdown.

The departments that still have to be funded account for about a quarter of the Federal Government, but still contain hundreds of thousands of employees who may not get a paycheck days before the Christmas holiday.

When asked about any advice for the public, Prof. Super said, “If there’s some office you need to contact, some information that you need, try to do it this week.”

SOME PASSPORT SERVICES WOULD SHUT DOWN, TOO

The consequences of inaction could be severe for millions of Americans across the country. At least seven federal departments and other agencies would feel the immediate effects of a shutdown, including Homeland Security, Transportation, and Agriculture.

If the Interior Department closes, so do many national parks.

If the State Department closes, so do some passport services for any holiday travel.

Emergency Management, law enforcement agencies, and other essential employees would still report to work like Transportation Security Administration (TSA) agents.

But be nice to them during the holidays. "Employees are forced to work without pay on the promise, which has always been kept in the past, that they'll be paid later," Super said.

Compounding the problem, many lawmakers — mostly GOP ones — who lost their seat in the midterms elections have already skipped town. The deadline to fund the government is Friday at midnight.

"If there's some office you need to contact, some information that you need, try to do it this week," Super said.