In the wake of that interview, White House press secretary Jay Carney was peppered with questions over whether Obama would require a return to the Clinton-era rates. Carney declined to answer the yes-or-no question, instead lambasting the GOP proposal as "magic beans and fairy dust."

Obama on Tuesday also said he was willing to make changes to entitlement programs but declined to commit to any specific program, a softer position than he took during debt ceiling negotiations last year with House Speaker John Boehner, R-Ohio. Republicans on Monday called for $600 billion in health savings that would be achieved by increasing the Medicare eligibility age from 65 to 67 and reducing Social Security benefits, among other measures.

The lack of specifics from the White House is part of its strategy to maintain leverage ahead of Jan. 1, when a string of tax increases and deep spending cuts take effect if leaders cannot reach a fiscal deal.

"Anytime you give a number, that gives people a target," said Martin Medhurst, an expert on presidential communication at Baylor University. "Obama is trying to preserve his options and not get caught laying out a specific number and then not be able to back off from it."

Or as a senior Democratic strategist with close ties to the White House explained, "The president is not going to negotiate with himself. There's no reason for him to make any firm declarations at this point. It can be frustrating for those watching the process, but he has the upper hand right now -- and Republicans know it."

In fact, Boehner received sharp criticism from some conservatives, who argued that he had ceded too much ground to Democrats on taxes with his own opening offer, pushing measures that would imperil fragile economic growth.

Obama hinted Tuesday that tax negotiations could be tackled as part of a two-step process: extending middle-class tax cuts before the end of the year and focusing on broader tax reform in 2013. Such an olive branch, the White House hopes, will convince some Republicans to give on higher tax rates for the wealthy -- a prospect that many conservatives dismiss as a nonstarter.