"The closer you are to the for-profit institutions that brought our economy to the brink, the easier it is for you to get a job in Washington. The more independent you are from those institutions, the more controversial a figure you are," Sirota told ABC News.
Warren is nothing if not independent. As the head of the Congressional Oversight Panel, a government watchdog created to oversee the controversial $700 billion Wall Street bailout, Warren routinely has criticized policies and decisions at Geithner's Treasury.
Her tenacity was on full display Wednesday when she ripped the foreclosure prevention program at a Senate Finance Committee hearing.
Blunt talk is par for the course for Warren, but not for Washington, where reports usually are written with more subtle language, composed in a type of hidden code. Warren likes to recall that in early 2009, an official on the Hill told her that one of the panel's initial reports was "too direct," suggesting that she take a more diplomatic approach.
"Well then what's the point?" replied Warren.
Since then, the Oklahoma native has stuck to her guns, even if it jeopardizes her possible appointment and confirmation to run the agency she has fought so hard for.
"This plain-spoken Oklahoman-speak that she uses is not what Washington's used to," a source familiar with the matter told ABC News. "She could be controversial because she's not attuned to the traditional way of doing business in Washington."
With her future the subject of a growing debate inside the Beltway, Warren knows she will be ultimately be picked or not -- and confirmed or not -- based on her body of work over the past few decades.
"She's going to be judged on her decades of academic scholarship and her abilities," the source told ABC, "and this idea that she might be found controversial is sort of inconsequential to her."
The financial industry, for its part, would like Obama to pick someone more likely to see their side of the issue, not just the consumers' side.
"We believe the Consumer Financial Protection Bureau should focus on both ends of the transaction," said Scott Talbott, chief lobbyist for the Financial Services Roundtable in Washington.
But if Obama wants to implement "the strongest consumer financial protections in history," as he called them on Wednesday, then progressives such as Sirota believe Warren should be the obvious choice to run the new bureau.
"The status quo has a reason to be nervous about Elizabeth Warren," Sirota said. "She is independent, she is eminently qualified, and she knows what problems need to be fixed. People who want to preserve the status quo are right to be worried that she'd challenge them, so it makes sense for them to challenge her confirmation by saying that she'd be too controversial."
At a time when the Wall Street reform bill has been denounced by some on the far-left for not doing enough to crack down on the financial system, the White House could win some liberal support by picking Warren.
"She has become a rallying point," Sirota said. "She'd go a long way towards selling that this bill is real progress."
On Wednesday, only 45 minutes into the Senate hearing, Warren got up from the witness table and headed for the exits. She had a more pressing engagement.
"I apologize for leaving and thank you all very much," she told the panel.