He foresaw the problems in 2002, and did nothing.
During recent decades, unsustainable increases in asset prices have been associated on a number of occasions with botched financial liberalization, in both emerging-market and industrialized countries. The typical pattern is that lending institutions are given substantially expanded powers that are not matched by a commensurate increase in regulatory supervision (think of the savings and loans in the United States in the 1980s). A situation develops in which institutions can directly or indirectly take speculative positions using funds protected by the deposit insurance safety net--the classic "heads I win, tails you lose" situation.
When this moral hazard is present, credit flows rapidly into inelastically supplied assets, such as real estate. Rapid appreciation is the result, until the inevitable albeit belated regulatory crackdown stops the flow of credit and leads to an asset-price crash. Bubbles of this type may be identifiable to some extent after they have begun, but the right policy is to do the financial deregulation correctly--that is, in a way that does not allow speculative misuse of the safety net in the first place. Or failing that, to intervene and fix the problem when it is recognized.
http://www.federalreserve.gov/boarddocs/speeches/2002/20021015/default.htmThanks a lot. Oh wait, wasn't Greenspan the Fed Chairman then, expressing his approval for subprime lending, cheered on by the Bush Treasury?