"Anna's leadership is marked by integrity, inclusiveness and bipartisanship, critical qualities in a committee leader," Pelosi wrote. "She advocates in the committee and in the House for healthcare, consumer protections, the environment and access to technology and issues related to women and children.
"Anna's leadership, vision, values and progressive commitment to the future gives us the opportunity to newly invigorate the debate," Pelosi added.
Eshoo is currently the fifth-ranked Democrat on the Energy and Commerce panel, behind Reps. Waxman, John Dingell (Mich.), Pallone and Bobby Rush (Ill.). But Waxman and Dingell are both retiring at the end of the year, and Rush has been on an extended leave to tend to his wife, who is ill.
Pallone's office issued a statement Thursday suggesting the New Jersey Democrat is confident that his record will be rewarded.
"Buoyed by broad support throughout the Caucus, Congressman Pallone is eager to continue in the traditions of Congressmen Dingell and Waxman as the next Democratic Leader of the Energy and Commerce Committee," a spokesman said.
The public letter marks a strategic departure for Pelosi when it comes to committee races. Although she's the party leader – and sits atop the Democrats' Steering and Policy Committee, which plays a major role in deciding committee posts – she almost never makes her leanings public, preferring instead to operate behind the scenes.
One Democratic aide said the move to come out for Eshoo so many months ahead of the election is indication that Pallone, who is senior to Eshoo on the panel, is leading the contest, and that “Pelosi doesn't like what direction things are heading.”
“I don't think this changes anything,” the aide added.
Breaking with Pelosi, Rep. Steny Hoyer (Md.), the second-ranked House Democrat, is backing Pallone.
Pallone and Eshoo both announced their intention to replace Waxman last month, setting off a fierce lobbying campaign targeting fellow Democrats.
A Caucus election to decide the contest will take place after November's elections.
This story was posted at 1:15 p.m. and updated at 4:09 p.m.