A group of Democratic senators will send the White House a letter today calling for Federal Reserve Vice Chairman Janet Yellen to succeed Ben S. Bernanke as head of the U.S. central bank.

One-third of the 54-member Senate Democratic caucus has signed the letter, which praises Yellen and encourages the president to nominate her, according to three Senate aides who asked not to be identified discussing internal matters. While the letter doesn’t name any other candidate, former Treasury Secretary Lawrence Summers is another potential nominee.

Bernanke, whose second four-year term expires Jan. 31, hasn’t indicated whether he would seek or accept a third term. President Barack Obama said last month that the Fed chairman has stayed in the post “longer than he wanted.” White House officials have begun to focus on how Obama will leave his mark on the central bank.

The letter campaign, led by Senator Sherrod Brown of Ohio, demonstrates the support that Yellen is gaining for the nomination and the uphill struggle that Summers could face in winning Senate confirmation, if nominated.

Senators Jeff Merkley of Oregon and Tom Harkin of Iowa are among the other senators who’ve signed the letter. Brown said earlier this week he supported Yellen.

“She’s done well as part of the Fed in the last months and months,” Brown, a member of the Senate Banking Committee, said in an interview on July 23. “She really has been a cool, smart head. To mix metaphors here, she has her hand on the public pulse, I think, better than your traditional Fed governors or presidents, and I think that would matter.”

First Woman

Yellen, the No. 2 Fed official since 2010, would be the central bank’s first female leader in its 100-year history. She was a University of California, Berkeley, economics professor who specialized in labor market research before serving as chairman of President Bill Clinton’s Council of Economic Advisers and president of the San Francisco Fed.

House Democratic Leader Nancy Pelosi said “it would be great to have a woman” to run the Fed. Yellen is “extremely talented,” the California congresswoman said in an interview on Bloomberg Television’s “Political Capital with Al Hunt,” airing this weekend.

“I just don’t recall one party banding together like this,” said Nick Sargen, a former San Francisco Fed economist who oversees $45 billion as chief investment officer at Fort Washington Investment Advisors in Cincinnati. “The Fed in the past has fought for its independence and it wants to be viewed as not part of the political process, so you could argue that this is a movement towards more politicization of the Fed.”