Another five Democrats - Congressman Conor Lamb (Pennsylvania) and Representatives-elect Jason Crow (Colorado), Jared Golden (Maine), Mikie Sherrill (New Jersey) and Abigail Spanberger (Virginia) - have made firm statements saying they would not vote for Pelosi but did not sign the letter.
Congressman Tim Ryan, who mounted an unsuccessful campaign against Pelosi two years ago, and Congressman Seth Moulton are leaders of the current effort to topple her.
But Pelosi does still have a math problem.
The letter's release suggests that rather than spending the next six weeks focusing on a fresh agenda to present to Americans, House Democrats could be consumed with a bitter and attention-grabbing internal leadership fight.
Either way, the letter also includes the signatures of Ben McAdams (D-Utah) and Anthony Brindisi (D-N.Y.), whose races haven't been called, meaning it's possible there are only 14 Democrats effectively pledged against Pelosi at the moment.
U.S. Rep. -elect Jeff Van Drew (D-2) today threw in with 16 other Democrats formally promising to vote against Nancy Pelosi's bid to be House speaker.
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"When we finally get into the majority I think we have to do all we can to keep these new members here, to support them in whatever campaign promise that they made", Rice told reporters last week. Pelosi spent Friday meeting with some of these incoming freshmen, a continuation of outreach she has been conducting since House Democrats prevailed in the midterm elections.
Pelosi (D-Calif.) is facing a growing "Never Nancy" revolt in her bid to regain the gavel she held between 2007-11, the last time Democrats controlled the House, and Rep. Marcia Fudge (D-Ohio) is mulling a leadership challenge.
With a narrow Democratic majority, now at 230 seats, she does not have much cushion to secure the 218 votes needed on the floor if all Republicans vote against her, as expected. Numerous freshman Democrats who avoided questions about whether they'd back Pelosi met with her last week, and are now on-record as supporting Pelosi's bid. Those Democrats, many of whom are in Republican-leaning districts, are being asked to go back on their word within the first hour they're in Congress.
Others signing the letter were incumbents Jim Cooper of Tennessee; Bill Foster of Illinois; Brian Higgins of New York; Stephen Lynch and Seth Moulton of Massachusetts; Ed Perlmutter of Colorado; Tim Ryan of Ohio; Kurt Schrader of OR; and Filemon Vela and Texas. "She deserves this victory, she earned it", he said. Such a situation is certainly one Democrats would like to avoid. But that ultimate number is dependent on the ultimate size of the majority; if it increases to 233, she can lose 15 votes.
Pelosi has repeatedly expressed confidence she'll return to the speakership. "Come on in, the water is warm", she said.