Securities and Exchange Commission Chairman Harvey Pitt said Sunday he will not resign despite criticism he has been a lax market regulator.

"I'm the right person for the job," Pitt said.

He contended the SEC has acted under his leadership more aggressively against corporate malfeasance than ever before.

Pitt said the public "expects me to be in there pitching for them."

Pitt used to represent Wall Street's big players as a private securities lawyer before President Bush named him last spring to head the SEC. He said he gave up his private work "a long time ago to serve the American public."

He said the SEC is more effective and aggressive than ever in investigating and punishing companies, executives and accountants. He denied charges the agency is "being light on anybody."

Commerce Secretary Donald Evans, a close Bush friend, said on Fox News Sunday that Pitt "is doing a terrific job."

Asked whether Evans thought Pitt's job was secure with the president, the secretary replied: "Harvey Pitt doesn't report to me. I'm not Harvey Pitt's boss."

"We are setting records every day, and I'm proud of my staff," Pitt said on NBC's Meet the Press.

"I believe the SEC has to be vigorous and tough," and the record under his watch shows that, Pitt said. He railed against politicians "who are trying to push their own agendas" by focusing attention on whether he should remain in the job.

Sen. Joseph Lieberman, D-Conn., said he thought "it would be better for everyone if Mr. Pitt stepped down" to give Bush "the opportunity to appoint somebody totally independent."

Lieberman said Pitt's former ties to the accounting industry creates too much potential for conflict.

Bush, hearing calls from Democratic leaders and some Republicans — notably Sen. John McCain, R-Ariz., for Pitt's resignation — is standing behind the chairman. The president said last week that Pitt "was put in place to clean up a mess, and he's working hard to do that."

The Associated Press contributed to this report.