Sen. Olympia Snowe, R-Maine, told CNN's "State of the Union" that she expects Congress will vote to extend tax cuts for incomes below $250,000 -- perhaps below $400,000 -- before midnight Monday. A Senate agreement "would build momentum" for the move in the House, she said.

"I think it would be horrific for the country if at this time, the final days of this legislative session that already has reached historic proportions of failure, that we would now culminate in failure to extend these tax cuts," said Snowe, who is on her way out of office.