"I think that's an old, tired cry," said spokesman Ari Fleischer. "It's a political charge that has no merit in substance."

A recent Senate report said the SEC had been lax in enforcing regulations some say could have prevented the large-scale accounting fraud that led to the spectacular collapse of erstwhile energy-giant Enron, as well as slow in punishing disgraced executives who built fortunes on such wrongdoing.

The SEC "has announced a record number of enforcement actions, has seized money from corporate officials who never should have had that money in the first place as a result of their shady transactions, and has taken that money back from those officials," Fleischer countered.

Key opposition Democrats have also called for Pitt to leave because of conflict of interest questions arising from his past role as key lobbyist for the accounting industry.