CNBC Video - David Walker With Joe Kernen On Squawk Box - Aug. 2, 2011
"We are less than three years away from where Greece had its debt crisis as to where they were from debt to GDP," he said.
The US is nearing the 100 percent threshold which historically shaves about one percentage point off GDP, which was just 1.3 percent for the second quarter and 0.4 percent for the first quarter.
With the recent increase in the debt ceiling and continued higher budget deficits at the federal level, the US is on course for its own crisis, Walker said.
"We are not exempt from a debt crisis," he said. "We're never going to default, because we can print money. At the same point in time, we have serious interest rate risk, we have serious currency risk, we have serious inflation risk over time. If it happens, it will be sudden and it will be very painful."