Sen. Elizabeth Warren wrote a ‘Dear Barack” letter asking the President to dismiss Mary Jo White as Chair of the SEC, the latest and strongest push by the Massachusetts Democrat to criticize the top markets cop and to influence financial policy-making here.

A White House spokesperson replied:  “The president continues to believe that Chair [ Mary Jo] White is the right leader for the Securities and Exchange Commission.”  This isn’t the first time the White House has come to Ms. White’s defense in response to criticism from Sen. Warren.

The strategy builds on efforts by progressives to block Obama administration nominees seen as too close to big business. Ms. White, an independent who was sworn in as SEC chief in April 2013, had been a prominent federal prosecutor and had also worked as a top corporate attorney.

The progressive group claimed a win one year ago when Antonio Weiss (with Wall Street ties) was essentially denied an opportunity to serve in a key Treasury Department position. He ended up as a top adviser to Treasury Secretary Jacob Lew. Ms. Warren and her allies were also instrumental in torpedoing consideration of a well-known corporate securities lawyer for an SEC post last year. That post remains unfilled.

At present, and among other things, Ms. Warren takes issue with Chairperson White’s decision not to craft a rule requiring public companies to disclose their political spending activities - even though the agency is restricted by law from working on such a rule this year. The senator also denounced an initiative to eliminate duplicative or outmoded corporate disclosures - a project Ms. Warren dubbed a “far-reaching, anti-disclosure initiative.”

A string of recent SEC chairpersons, including Mary Schapiro and Elisse Walter, have defended Ms. White’s record.