With turnover at the S.E.C., Ms. White’s legacy could be in jeopardy as well.

She oversaw a record number of enforcement actions and directed a rapid pace of rule-writing based not only on Dodd-Frank, but on regulations of her own making. Those initiatives were aimed at improving money market fund regulation and the broader asset management industry.

“I think what we’ve done so far has been quite transformative and really modernized that core responsibility,” Ms. White said in a recent interview.

Yet Ms. White has not completed more than a dozen rules, nor has she formalized a plan to require that financial advisers act in their clients’ best interests. Now that these initiatives will fall into the hands of a Republican chairman, they may come off the agenda.

As it was, Ms. White, a political independent, drew criticism from liberal lawmakers who view her as the quintessential moderate. Senator Elizabeth Warren, the Massachusetts Democrat who channels the populist outrage over Wall Street excess, even called on President Obama to designate a new S.E.C. leader because the agency had not required companies to disclose political contributions.

In her first public remarks on the subject, Ms. White said in an interview that the criticism “really does come with the territory.”

“I think I’m a very constructive recipient of constructive criticism,” she said, adding: “It’s not like you like people to beat on your head, whoever they are, however baseless it is.”

Before the S.E.C., Ms. White was the first woman to become United States attorney in Manhattan, one of the most apolitical jobs in government. Earning a reputation as a tenacious prosecutor with an independent streak, Ms. White embraced the joke that her office was the United States attorney for the “sovereign,” rather than Southern, district of New York.