Treasury head: Only option is to raise debt limit

Plan A: Raise the debt ceiling. Plan B: (See plan A).

Even with Congress gridlocked over how to do it, Treasury Secretary Timothy Geithner says there is no alternative to raising the debt ceiling, and that he is "absolutely" convinced that it will get done.

"Our plan has been -- and the only plan available -- is for Congress to act," Geithner said Monday morning on CNBC's Squawk Box. "There is no plausible way to run the country… if we are not paying our obligations.... It's not feasible."

Geithner also said that the August 2 deadline (a date that many GOP lawmakers have dubbed "arbitrary") is still firm.

"We've looked at this carefully," he said. "We have no other options to give Congress more time." While some members doubt the importance of the date, Geithner said that leadership "understands" the date is real.

Geithner would not say how he expected the deal to play out, but said that under no circumstances would it involve the dismantling of Social Security and Medicare, and that it must include "modest" revenue increases.

He also said that the Reid-McConnell plan, which would give the president the power to raise the debt ceiling himself, could have the effect of ensuring that "politics can't stand in the way" of a solution.