WASHINGTON -- At a briefing with reporters on Wednesday, President Obama was asked whether he believed that the debt ceiling was constitutional or whether the 14th Amendment required the government to meet all of its obligations regardless of the debt-limit statute.

Obama dodged the question. "I'm not a Supreme Court Justice, so I'm not going to put my constitutional law professor hat on here," he said about the debt ceiling and a question on the war in Libya.

Treasury Secretary Tim Geithner, however, is less afraid of wearing that hat. At a Politico Playbook breakfast on May 25, Geithner was asked by host Mike Allen about the negotiations over default and the debt ceiling.

"I think there are some people who are pretending not to understand it, who think there's leverage for them in threatening a default," Geithner said. "I don't understand it as a negotiating position. I mean really think about it, you're going to say that-- can I read you the 14th amendment?"

Geithner whipped out his handy pocket-sized Constitution. Allen tried to brush it aside. "We'll stipulate the 14th Amendment," he said.

"No, I want to read this one thing," Geithner insisted.

"It's paper clipped!" Allen observed, noting that Geithner's copy of the Constitution was clipped so that it would open directly to the passage in question.

"'The validity of the public debt of the United States, authorized by law, including debts incurred for the payments of pension and bounties for services in suppressing insurrection or rebellion' -- this is the important thing -- 'shall not be questioned," Geithner read.

Watch Geithner:

"So as a negotiating strategy you say: 'If you don't do things my way, I'm going to force the United States to default--not pay the legacy of bills accumulated by my predecessors in Congress.' It's not a credible negotiating strategy, and it's not going to happen," Geithner insisted.

On Tuesday, HuffPost reported that rank-and-file Senate Democrats are increasingly looking at the 14th Amendment as a solution to the default impasse. The Treasury Department says that on Aug. 2, the government will no longer have the ability to meet its obligations without raising the debt ceiling and will default, sending capital and bond markets into chaos.

The conservative blog RedState suggested Thursday that if Obama embarked on such a course, House Republicans would be wise to begin impeachment proceedings. The Democratic-controlled Senate would be unlikely to go along, however, embroiling Washington in a constitutional crisis. Republicans impeached a Democratic president in 1998 and suffered politically for the overreach. Impeaching the president for insisting on paying past bills on time could be equally devastating for the GOP.

Nearly a month before Geithner read the Constitution to a gathering of reporters, Bruce Bartlett floated the option of 14th Amendment invocation in The Fiscal Times.

The news that Senate Democrats were considering the option was reported on Countdown with Keith Olbermann on Current TV Tuesday. Watch: