By Alicia M. Cohn - 12/02/12 03:20 PM EST
Republican leaders in Congress have rejected the proposal, with Speaker Boehner (R-Ohio) calling it "not serious."
Geithner, who spoke earlier on CNN, defended the administration's plan as a "very comprehensive, very carefully designed mix" of increased revenue and spending cuts. He said the proposal is "a good basis for these conversations."
Ayotte disagreed and said the White House had failed to match the GOP's openness to new revenues in a deficit deal.
Although Republicans have indicated they are willing to consider new revenue through tax code reform -- a major concession Ayotte called "very difficult" -- they are not willing to consider raising tax rates for any Americans. Obama wants to allow current lower tax rates to expire, raising rates on American families making more than $250,000 annually.
The White House has said there will be no agreement if the GOP does not agree to raise tax rates on the "top 2 percent" of income-earners.
Sen. Mark Warner (D-Va.), appearing alongside Ayotte on CNN, was more optimistic about the two sides reaching a deal despite past failures in negotiating the deficit and debt ceiling.
"One of the reasons why I think this time it's going to be different from times in the past ... is the American people," he said.
Warner's comment is likely a reflection of the confidence Democrats have, coming out of the election, that they have the most leverage in negotiations. According to an ABC News/Washington Post poll released last week, more than six in 10, or 61 percent, of registered voters say they support the plan to increase taxes on those making above $250,000 per year.