House Democrats could soon be at war.  

The internal drama over who will take the top Democratic slot on the Energy and Commerce Committee next year has spilled into public view, with some lawmakers unhappy with Minority Leader Nancy Pelosi for taking sides so early — or at all.  

Pelosi stunned colleagues on Thursday with a letter outlining support for her fellow Californian and close friend Anna G. Eshoo against Frank Pallone Jr. of New Jersey, and now some Democrats find themselves in a difficult position. House Democrats put significant stock in years of service when doling out plum committee assignments, and the simple choice of picking the Energy and Commerce Committee’s current No. 3 — Pallone — now has been complicated by Pelosi’s endorsement of Eshoo, who is No. 5 in seniority.  

Many lawmakers and aides told CQ Roll Call they don’t see stark enough differences between the members to justify waiving the seniority precedent and allowing Eshoo to leapfrog over Pallone. Both lawmakers, they have argued, are equally able to do the job, and there is little reason for Pelosi to choose sides so publicly in a move surely aimed at influencing undecideds.  

One House Democrat said Pallone has paid his dues.  

As leadership’s point person for coordinating the party’s messaging on the House floor, Pallone has been “a loyal lieutenant,” said the lawmaker, who asked to remain anonymous and still hasn’t decided whom to back. “It’s a thankless task, it’s drudgery, and he does it every day. And Pelosi threw him out like yesterday’s trash.”  

Eshoo boosters see it differently.  

“I think Frank Pallone has done a really good job heading our messaging team, but I think Anna Eshoo is a woman who’s dynamic, who is from the high-tech community out in California, and can bring some real energy to Energy and Commerce,” said New York’s Nita M. Lowey, who became ranking member of the House Appropriations Committee without being the next in line.  

But seniority is an especially sensitive issue for the Congressional Black and Hispanic caucuses, whose members believe that giving deference to tenure is the only way to protect minority members from slights, accidental or intentional, in getting promoted on Capitol Hill.  

The CBC in particular is poised to benefit from respect for the seniority system: Its members currently hold ranking member slots on five of the 22 House committees, and that number could increase to seven in the 114th Congress. CBC members are inching ahead on a number of other panels, too, painting a viable picture of a day when they could wield unprecedented influence on just under half of all House committees.  

Many of them did not take kindly to Pelosi’s public disregard for precedent.  

“She officially buried the concept of seniority today,” Charles B. Rangel of New York said Thursday.  

“I respect those who respect that system,” Eshoo stressed to reporters in early February. “It’s been around a long time. But I don’t believe it’s sacrosanct.”  

Arizona Rep. Raúl M. Grijalva, who launched an unsuccessful bid last year against more-senior Oregon Rep. Peter A. DeFazio for ranking member of the Natural Resources Committee, believes a transformed caucus has shifted the norms.  

“Pallone’s saying, ‘It’s my turn, it’s my seniority,’ and I don’t have a problem with him doing that …  but with almost 50 percent of our caucus members being members of the Democratic Caucus with six years or less under their belts, then maybe for the seniority question, attitudes are changing.”  

While it surprised no one that Pelosi would support Eshoo to succeed retiring Rep. Henry A. Waxman, D-Calif., party leaders have often avoided involving themselves publicly in contentious leadership races. It’s also exceedingly early for the minority leader to be making such a major power play, with ranking member elections not taking place until after the November midterms.  

Pelosi’s most public entrance into the fray came in 2006, when she backed her close ally Rep. John P. Murtha of Pennsylvania to be the majority leader as she assumed the speakership in the new Democrat-controlled House. Despite her relentless whip effort, Murtha lost to Steny H. Hoyer of Maryland, who is said to now be working behind the scenes on Pallone’s behalf.  

(In 2010, Ways and Means Committee members revolted  when Pelosi wanted Rep. Pete Stark of California to hold the gavel.)  

An endorsement from the House’s most powerful Democrat certainly won’t hurt Eshoo’s chances. Inside observers said that the show of support will undoubtedly influence some undecided members, though they cautioned that like the Murtha brawl, it won’t be a game-changer.  

If anything, lawmakers and aides said Thursday, the letter Pelosi sent Democrats just called attention to how Eshoo is falling behind Pallone, and how much Pelosi felt her friend and ally needed a boost.  

A chief of staff to a House Democrat who is backing Pallone called Pelosi’s letter a “Hail Mary,” adding, “It’s desperate.”  

Even a senior member of the House Democratic Caucus who happens to back Eshoo called it “a bit peculiar.”  

Waxman announced he would not seek re-election on a Thursday morning; sources said that by Thursday afternoon, Pallone was already making calls to shore up support among his peers. As gauche as it might have seemed, those hours proved pivotal to giving Pallone an early lead . Eshoo waited until the weekend to start speaking publicly about her intentions.  

There have been a number of instances in recent history where members were more inclined to turn a blind eye to the unofficial seniority rules.  

In 2012, Lowey was selected over Rep. Marcy Kaptur of Ohio for ranking member of the Appropriations Committee; in 2010, Rep. Elijah E. Cummings of Maryland was picked over Rep. Carolyn B. Maloney of New York to be the most effective foil to bombastic Oversight and Government Reform Chairman Darrell Issa, R-Calif.  

And in 2008, emboldened by colleagues clamoring for a more progressive legislative agenda on climate issues, Waxman ousted longtime Energy and Commerce Committee Chairman John D. Dingell, D-Mich.  

Eshoo supporters counter that there is good reason not to reward Pallone: It’s no secret, they say, that he has always had Senate aspirations, and just as recently as last year challenged Democrat Cory Booker for the late Sen. Frank R. Lautenberg’s seat.  

A source close to Pelosi insisted that friendship, loyalty and regional alliances had nothing to do with her decision to endorse Eshoo. The source said the minority leader “feels this is all about the future of the caucus.”