Lieberman says we're likely to tumble over cliff

(CNN) – With the president and Congress on Christmas vacation - and no deal struck on avoiding the fiscal cliff - one retiring senator predicted Sunday that Washington would be bustling with negotiations as the clock ticks toward 2013.

"We're going to be here New Year's Eve," Sen. Joe Lieberman said on CNN's "State of the Union," offering less-than-rosy prospects for the possibility of a debt-reduction deal by midnight on December 31.

"In the aftermath of House Republicans rejecting Speaker (John) Boehner's so-called Plan B, it's the first time I feel it's more likely that we'll go over the cliff than not," he said, referring to the failed attempt by the GOP leader to extend tax breaks for Americans making under $1 million. Boehner, sensing he lacked enough support from House Republicans, scrapped a vote on the measure Thursday night.

Explaining the Plan B breakdown Sunday, Rep. Mick Mulvaney, a Republican from South Carolina, said GOP members were wary of voting on a measure that stood no chance of passing the Senate and being signed by President Barack Obama.

He also pushed back on suggestions the episode reflected a failure of leadership from Boehner, pointing to broad opposition to the Plan B measure from both moderate and conservative Republicans.

"This was not a fight that divided conservatives and moderates within the party," Mulvaney said, also on "State of the Union." "This was a legislation-specific vote and not a vote on leadership."

Lieberman told CNN chief political correspondent Candy Crowley on Sunday that failing to meet the year-end deadline on striking a deal would amount to "the most colossal, consequential act of congressional irresponsibility in a long time."

"Maybe ever in American history, because of the impact it will have on almost every American," he said.

The remaining option, Lieberman said, is a smaller deal brokered in the Senate to stave off large across-the-board spending cuts set to be enacted at the beginning of next year.

"I've talked to a lot of Republican colleagues in the Senate who are favorably inclined toward the idea to protect the middle class from the tax cuts," he said. "Let's raise taxes on people over $250,000, and let's stop those terrible cuts in defense, homeland security, education."