(CNN) -- Both sides are refusing to stand down ahead of a tentative Senate vote currently scheduled for the wee hours Monday morning on whether to end the government shutdown.
Senate Majority Leader Mitch McConnell and Minority Leader Chuck Schumer each took to the chamber floor on Sunday to trade blame for the shutdown, each accusing the other side of taking hostages.
McConnell said Democratic demands on permanent protections for recipients of the Deferred Action for Childhood Arrivals program were not an emergency given that the program is not set to expire until March. He said the expired Children's Health Insurance Program and other government programs were of more immediate concern.
"All of these other things are an emergency," McConnell said. "The one non-emergency issue that our friends on the other side are trying to shoehorn into this discussion doesn't reach that status of emergency until March."
McConnell said he supported the right of the Democratic minority to filibuster "from an institutional point of view," but maintained Schumer's use of it was unproductive and that the Democrats should relent.
Schumer, meanwhile, pinned blame for the shutdown on Republicans in general and the President foremost.
"Congressional leaders tell me to negotiate with President Trump," Schumer said. "President Trump tells me to figure it out with the congressional leaders."
Schumer said he offered Trump a compromise on immigration that included funding his proposed border wall with Mexico, but that ultimately Trump and the Republicans had not moved on his proposal.
"Because the President campaigned on the wall, even though he said it would be paid by Mexico, and demands the wall, for the sake of compromise, for the sake of coming together, I offered it," Schumer said. "Despite what some people are saying on TV -- and mind you these are folks not in the room during discussion -- that is exactly what happened. The President picked a number for a wall. I accepted it."
Earlier Sunday, the White House called for Senate Republicans to change the chamber's rules to resolve the funding impasse as the government shutdown continued into its second day.
Trump tweeted his call for Senate Majority Leader Mitch McConnell to invoke the so-called nuclear option and thereby remove leverage for Senate Democrats.
"Great to see how hard Republicans are fighting for our Military and Safety at the Border. The Dems just want illegal immigrants to pour into our nation unchecked. If stalemate continues, Republicans should go to 51% (Nuclear Option) and vote on real, long term budget, no C.R.'s!" Trump tweeted.
A spokesman for McConnell said in response to the tweet that the Senate Republican Conference does not support changing the 60-vote rule, a reiteration of Republican Senate leadership's already-stated opposition to the move Trump has called for over the past year.
Senate rules impose a threshold of 60 votes to break a filibuster, and Senate Republicans currently hold a slim majority of 51 votes, meaning even if they can unite their members, they need nine more votes to end debate. The White House is calling for the Senate to change its rules and move the threshold to a simple majority of 51 votes.
Eliminating the 60-vote threshold to break a legislative filibuster would remove significant powers for the minority party in the Senate, and party leaders have been reluctant to do so in the past because of the consequences it would pose when their party returns to the minority.
White House budget director Mick Mulvaney said on CNN's "State of the Union" that eliminating the filibuster would be one avenue they back to ending the shutdown.
"There's a bunch of different ways to fix this," Mulvaney said. "We just want it to get fixed."
Mulvaney offered that another way to end the shutdown, from their point of view, would be for enough Democrats to cross the aisle and give the GOP the votes it needs to restore funding.
"Get some of those Democrats who say back home they want to work in a bipartisan fashion, they want to work with Republicans, but don't," Mulvaney said.
Mulvaney said Schumer had not exactly offered the White House what they wanted on the wall, arguing Democrats had offered "to authorize" the wall, but not to appropriate funds for it.
'End of the Senate as it was originally devised'
Democratic Sen. Chris Coons of Delaware responded to the President's tweet calling for the nuclear option in an interview on "Fox News Sunday," suggesting it was unproductive.
"This is another example of President Trump throwing a tweet in the middle of bipartisan negotiations that are making progress," Coons said. "I think Senator McConnell, the Republican majority leader, in the end will have much more to say about how the Senate is run."
Senate Minority Whip Dick Durbin of Illinois said on ABC's "This Week" that eliminating the 60-vote threshold "would be the end of the Senate as it was originally devised and created going back to our Founding Fathers."
"We have to acknowledge our respect for the minority," Durbin said.
As routine use of the filibuster has increased over the years, debate has grown about its elimination. Last April, McConnell took the latest step to change the rule, triggering the nuclear option to break a filibuster on the confirmation of Neil Gorsuch to the Supreme Court.
Trump has called repeatedly for McConnell to move the Senate to simple-majority rule, and despite some backing from the House Republicans, the rules have remained. McConnell said in April that the "core of the Senate is the legislative filibuster" and that he was opposed to going "nuclear."