Energy and Commerce Chairman John Dingell (D-Mich.) is trying to strike into the heart of Rep. Henry Waxman’s (D-Calif.) base with a direct appeal to the 151 lawmakers who last month signed onto a letter that the California liberal penned outlining climate change goals.

The two lawmakers have been locked in a bitter battle for Dingell’s gavel since Waxman launched a surprise bid last week. Dingell on Friday wrote to Waxman’s co-signers to make the case that a draft climate change bill that he released days after the letter meshes with the targets that the lawmakers laid out.

“I think you will find the discussion draft aligns with the principles and goals outlined in your letter,˜ he wrote. Dingell attached an analysis that compares the goals in the letter with provisions in his proposed package.

Waxman’s allies have pointed to the long list of signatures on that Oct. 2 climate change letter as evidence of the deep support among Democrats for the veteran lawmaker’s leadership on the issue.

But Dingell supporters challenged that notion in a Friday afternoon conference call with reporters, noting that many — in fact, about a dozen — of those signing onto the letter have declared their support for the Wolverine State lawmaker in the chairmanship fight.

On that call, Rep. Mike Doyle (D-Pa.), a member of the Energy and Commerce panel and whip for Dingell in the contest, said he is confident Dingell will prevail next week — and by a healthy margin. Democratic lawmakers are expected to vote on the Energy and Commerce chairmanship on Wednesday or Thursday.

Of a buzzed-about deal that Democratic leaders could strike between Dingell and Waxman to defuse the battle, Doyle said, “there’s really nothing to discuss.” He said that because Dingell has run the committee “like a machine,” there is “no basis for removing him” and therefore “nothing to negotiate.”