The federal government's top small-business watchdog resigned last week after seven years of fighting to ease regulatory burdens  on smaller firms.

Thomas Sullivan, the chief counsel of the Small Business Administration's office of advocacy, said in a letter to President Bush that he was leaving government for the private sector effective Oct. 24.

Since 2001, Sullivan has helped small businesses save an estimated $65 billion in new regulatory costs by pressing federal agencies to comply with the Regulatory Flexibility Act.

Under his leadership, the office has also convinced 22 states to create similar small-business advocacy posts for local owners, while producing more than 25 entrepreneurial research reports every year. 

"I followed your counsel to always remember that my boss is the American taxpayer and to leave government better off for my service," Sullivan said in his letter to the president.