Duchy Trachtenberg’s supporters can’t seem to decide whether her Democratic primary opponent, District 1 Montgomery County Council incumbent Roger Berliner, is an environmental radical or a shill for developers.

After Berliner (D-Potomac-Bethesda) was endorsed by the Sierra Club a few weeks ago, one of Trachtenberg’s business community backers, Jim Soltesz, called the group “the most vicious anti-development, anti-growth organization in the country.”

Soltesz heads an engineering firm that has worked on numerous major building projects in the region, including the Peterson Companies’s unsuccessful plan for a major retail project near Clarksburg Town Center. Berliner was a major opponent of the project, as was the Sierra Club.

Now comes Democracy for America (DFA), the progressive political group founded by former Vermont governor Howard Dean. DFA, which has endorsed Trachtenberg, claims Berliner opened the door to construction in the environmentally fragile Ten Mile Creek watershed.

A recent e-mail blast from the group says in part:

“Berliner has voted to . . . approve a construction project right by Ten Mile Creek. After hearing Ten Mile Creek — one of the last clean creeks in the area — would be polluted by storm runoff from his construction project, a progressive voice pushed back. “

“Duchy Trachtenberg won’t stand for this failed leadership.”

Trachtenberg said Friday morning — just as she said after Soltesz’s broadside — that she had no idea the e-mail was going out and had nothing to do with it. Asked if she thought it was accurate, she declined to comment.

“Obviously it was strong progressive rhetoric,” she said.

DFA officials have not yet returned a phone message.

Berliner, who helped craft the County Council measure sharply limiting construction in the area, said the claim was absurd.

“Anyone who has followed the Ten Mile Creek issue knows what a gross distortion and misrepresentation of the facts this e-mail conveys,” Berliner said.