The bitter fight for control of the Energy and Commerce Committee enters its final day with the teams of both Chairman John Dingell (D-Mich.) and second- ranking Rep. Henry Waxman (D-Calif.) predicting victory, but with the outcome far from clear.

Waxman narrowly secured the nomination of the Democratic Steering and Policy Committee on Wednesday, and both sides sought to spin the results as evidence that they have the momentum heading into today’s Caucus-wide balloting.

With the gavel of one of the House’s most powerful panels hanging in the balance, whip teams for both lawmakers were set to work into the night, making calls to maintain support among committed lawmakers and sway those still undecided.

“The view on both sides is they have it locked up, and both sides will be making a lot of calls between now and [Thursday] morning,” a Waxman supporter’s aide said. “There’s nothing more uncertain than an internal election by secret ballot.”

Democrats will gather at 9 a.m. in the Cannon House Office Building Caucus Room to hear final appeals from both House veterans and then line up to cast secret votes. Because Waxman is the official nominee after the Steering Committee endorsement, his name will be submitted to lawmakers first. Then a Dingell supporter will have to stand to nominate the incumbent chairman. But Dingell won a coin toss Wednesday and has opted to present his case first to his colleagues.

It was unclear at press time Wednesday who each side has tapped to speak for them, or how long the process will take.

Dingell got a significant boost Wednesday from House Majority Leader Steny Hoyer (D-Md.), who spoke on his behalf before the Steering Committee, sources familiar with the session said. After speaking warmly of Waxman, Hoyer expressed concern at the precedent that would be set by removing Dingell, whom he described as a loyal House Democrat and able legislator, a senior Democratic aide said.

Hoyer commands deep respect and goodwill in the Caucus, but it is not clear what effect his endorsement will have, coming so late in the process. At least one other group on Wednesday heard the Marylander heap praise on Dingell. Hoyer turned up and made the case to more than a dozen incoming freshmen gathered for a morning fundraiser at the Democratic Congressional Campaign Committee. Dingell headlined that event with Natural Resources Chairman Nick Rahall (D-W.Va.), raising more than $400,000 to help the incoming Members retire debt, sources familiar with the event said.

The new class of freshmen remain something of a wild card. Waxman has been shoveling cash their way from his well-heeled leadership political action committee in recent weeks, and one lawmaker, speaking privately earlier this week, said the Californian had sewn up all but a few of them. But Rep.-elect Jim Himes (D-Conn.), who has fielded a call from Rep.-elect Mark Schauer (D-Mich.) on behalf of Dingell, said he is still weighing his options and is unsure which way his classmates are breaking. “This is obviously the first consequential vote I will take, so I really feel an obligation to study up on the records of both of the chairmen before I make a decision,” Himes said.

The camps of both contenders saw reason to be encouraged from the results of the Steering Committee vote, which Waxman won 25-22. Waxman backers noted that the Californian beat an incumbent to secure the nomination — no small feat in a Democratic Caucus that has traditionally held the seniority system as sacred.

“That indicates a lot of weakness of support” for Dingell, one aide to a Waxman supporter said.

But Dingell backers said they never expected to keep the margin so close in a committee stocked with allies of Speaker Nancy Pelosi (D-Calif.), who have largely fallen in behind Waxman. In fact, they argued, they could have won the vote — or at least held it to a single-vote margin — if the full panel had been voting. Dingell lost out on votes from Ways and Means Chairman Charlie Rangel (D-N.Y.) and Financial Services Chairman Barney Frank (D-Mass.), both of whom have endorsed him. A third Dingell supporter on the Steering Committee, Rep. John Tanner (D-Tenn.), was in Valencia, Spain, attending a meeting of the NATO parliamentary assembly.

Recent history suggests the Steering Committee’s nomination does not guarantee success. The last time Democrats faced a high-profile struggle for a top committee slot, in 1996, then-Banking and Financial Services ranking member Henry Gonzalez (D-Texas) failed to win the endorsement of the Steering Committee. But when the fight went to the full Caucus, Gonzalez, then 80 years old, managed to beat back challenges from Reps. John LaFalce (N.Y.) and Bruce Vento (Minn.), the panel’s second- and third-ranking Democrats.

In the runup to that contest, Gonzalez, a 35-year House veteran, faced criticism that he had effectively checked out of the job. That’s a charge that Dingell — who, while 82 and in a wheelchair as he recovers from knee surgery, remains mentally sharp by all accounts — has not seen from Waxman’s camp.

But Gonzalez also pledged to step down from his post after two years — a condition of a deal that Hoyer unsuccessfully tried to broker between Dingell and Waxman to defuse the current battle.