Greed, fearlessness, and bad government spurred the stock bubble that led to the most recent economic dire straits facing the U.S., National Economic Council Chairman Lawrence Summers asserted Friday.

"An abundance of greed and an absence of fear on Wall Street led some to make purchases -- not based on the real value of assets, but on the faith that there would be another who would pay more for those assets," Summers said Friday morning during an address at the Brookings Institution, a liberal think tank. "At the same time, the government turned a blind eye to these practices and their potential consequences for the economy as a whole."

"This is how a bubble is born," the former Treasury secretary added. "And in these moments, greed begets greed."

"In the past few years, we