WASHINGTON — In a blistering letter Tuesday, Sen. Elizabeth Warren, D-Mass., all but called Securities and Exchange Chair Mary Jo White an incompetent regulator.

“You have now been SEC chair for over two years, and to date, your leadership of the commission has been extremely disappointing,” Warren wrote. “At your confirmation hearing, you stated without reservation that you would implement a strong enforcement policy at the SEC.”

White is a former top federal prosecutor in New York, and her appointment to head the SEC was taken at the time to mean the agency would become a force to be reckoned with on Wall Street.

Instead, critics have complained that the SEC has gone soft on Wall Street. Liberal groups were incensed when White announced in late May that she was hiring a top lawyer from Goldman Sachs, Andrew “Buddy” Donohue, as her new chief of staff.

Particularly irking Warren, the SEC continues to settle cases with Wall Street firms and securities companies without requiring admissions of guilt.