WASHINGTON (AP) — More than 300 former campaign staffers and organizers for President Barack Obama have signed on to a letter urging Massachusetts Sen. Elizabeth Warren to run for president in 2016, the latest effort to nudge the Democrat into the race.

The Obama alums said in the letter released Friday that they want someone who will “stand up for working families and take on the Wall Street banks and special interests.” The letter was released by Ready for Warren, a grassroots group promoting a potential campaign.

Hillary Rodham Clinton remains the dominant Democratic figure in the early days of the next presidential campaign but has yet to announce a presidential campaign. The former secretary of state has drawn support from a number of top former Obama aides, including 2012 campaign manager Jim Messina, who are involved in outside groups preparing for the 2016 race. 

But the letter from dozens of former Obama field organizers and campaign staffers shows the interest in a Warren campaign even though she says she’s not running. Noting the tone of the letter, Warren spokeswoman Lacey Rose said the senator “has been pointedly questioning the Wall Street-centric culture that has existed at Treasury and understands that various insiders find that threatening.”

Some of the former campaign aides who signed the letter include: Rajeev Chopra, the chief information officer for Obama’s 2012 campaign; Stephen Geer, who led email and online fundraising in 2008; and Sam Graham-Felsen, the campaign’s chief blogger in 2008.

Warren, a favorite of liberals, has been courted by the left. MoveOn.org announced earlier this week that it was starting a draft Warren campaign and promoting Warren in early presidential states Iowa and New Hampshire.