Congress is down to the last day - with no fiscal cliff plan to vote on, at least not yet.

Senatorsfailed Sunday to come up with a bipartisan proposal to head off aseries of tax hikes and spending cuts set to start taking effectTuesday. The White House served notice it may push its own plan and dareRepublicans to oppose it.

"Republicans will have to decide ifthey're going to block it, which will mean that middle-class taxes do goup," Obama said on NBC's Meet The Press.

Optimism rose andfell throughout the day as officials from Capitol Hill to the WhiteHouse dickered over budget details, worked the phones, spoke withreporters - and generally blamed each other for the impasse over a dealto avert higher taxes on all Americans, massive cuts to major programsand a possible recession as a result.

The House and Senate planned to meet Monday, a rarity for New Year's Eve, in hopes of having a tentative agreement to consider.

"Somethinghas gone terribly wrong when the biggest threat to our American economyis the American Congress," said Sen. Joe Manchin, D-W.Va.

The day began with the Meet the Pressinterview in which Obama said he remains hopeful of a deal, but he madeit clear he would hold Republicans responsible if the nation goes overthe fiscal cliff.

"The way they're behaving is that their onlypriority is making sure that tax breaks for the wealthiest Americans areprotected," Obama said.

If necessary, Obama said, he would pushfor a vote on a pared-down plan that includes a renewal of unemploymentinsurance and an extension of the George W. Bush tax cuts formiddle-class Americans who make less than $250,000 a year.

All theBush tax cuts are set to expire Tuesday. Senate Majority Leader HarryReid, D-Nev., who spoke with Obama by phone during the day, said he mayput such a plan on the floor when the Senate reconvenes Monday.

"If Republicans don't like it, they can vote no," Obama said.

Republicans pointed the finger right back at Obama.

HouseSpeaker John Boehner, R-Ohio, said Obama has always emphasized tax hikesahead of spending cuts, especially when it comes to the fast-risingentitlement programs of Social Security and Medicare.

"Americans elected President Obama to lead, not cast blame," Boehner said in a statement.

Onthe Senate floor, McConnell said he called Vice President Biden "to seeif he could help jump-start negotiations on his side." The Republicanleader noted that he and Biden have worked well together during previousbudget battles.

The two "continued their discussion late into the evening(Sunday) and will continue to work toward a solution," said McConnellspokesman Don Stewart, pledging "more information as it becomesavailable."

As Reid adjourned the Senate early Sunday evening, he said, "We are apart on some pretty big issues."

During the negotiations, McConnell said, "I'm concerned with the lack of urgency here. There's far too much at stake.

"Thereis no single issue that remains an impossible sticking point," he said."The sticking point appears to be a willingness, an interest or courageto close the deal."

In one sign of movement, Republicans dropped ademand to slow the growth of Social Security and other benefits bychanging how those payments are increased each year to allow forinflation.

Once again, the conflict between the Democratic president and the Republican House has shadowed a budget dispute.

Ithappened during the near-government shutdown in the spring of 2011. Ithappened again that same year when the government nearly defaultedduring a dispute over the debt ceiling.

As in those previousdisputes, the fiscal cliff talks revolve around taxes and spending cutsthat could help reduce a federal debt that exceeds $16 trillion.

Obamaand the Democrats have emphasized higher tax rates on the wealthiestAmericans. Republicans have balked at tax hikes and emphasize spendingcuts instead.

Despite their opposition, Republicans pretty much expect that taxes on wealthier Americans are going to rise.

"Thepresident won. The president campaigned on raising rates, and he'sgoing to get a rate increase," Sen. Lindsey Graham, R-S.C., told ABC.But "this deal won't affect the debt situation."

In his NBCinterview, taped Saturday, Obama said he has offered Republicans aconcession that would reduce Social Security spending by changing theway cost-of-living increases are calculated.

Obama's aides proposed an agreement that would reduce the deficit by $2.4 trillion over 10 years, about half in spending cuts.

"The offers that I've made to them have been so fair that a lot of Democrats get mad at me," Obama said.

Managingthe fiscal cliff is essential to improving the economy, the presidentsaid. The nation is poised to improve economic growth in 2013, he said,"but what's been holding us back is the dysfunction here in Washington."

Sen.Tom Coburn, R-Okla., said, "We're stuck because many in Congress wantto move toward Clinton-era tax rates but not Clinton-era spending."

The president did not make a public appearance Sunday, instead monitoring events from inside the White House.

He did sign one bill: a five-year extension of the Foreign Intelligence Surveillance Act.