Reid advised his fellow senators to "hang loose" in the event that a deal is reached and a vote comes up later this evening.

"At some point in the negotiating process, it appears that there are things that stop us from moving forward," he said. "I hope we're not there, but we're getting real close. And that's why I still hold out hope that we can get something done. But I'm not overly optimistic, but I am cautiously optimistic that we can get something done."

Meanwhile, during his prayer to open the Senate this afternoon, the Senate's chaplain appealed to a higher power to assist in the "fiscal cliff" fight.

"Let us feel your presence today on Capitol Hill," said Senate Chaplain Barry Black. "Look with favor on our nation and save us from self-inflicted wounds."

Following a brief recess for Christmas, members of Congress returned to Washington on Thursday, scrambling to patch together even a makeshift bridge across the "cliff" at year's end, when a series of tax hikes and spending cuts is scheduled to go into effect, potentially hurling the U.S. economy into a dangerous recession.