DENVER—-Mayor Adrian M. Fenty’s strained ties with the labor community erupted into an all-out feud at the Democratic National Convention today, with D.C.’s main labor organizing group threatening to picket the mayor at future national appearances.

A flier provided to the D.C. delegation at breakfast here today decries Fenty as a “budget-shattering, union-busting, promise-breaking political boss,” calling Hizzoner out for his administration’s bungling of the summer jobs program, for schools opening “in turmoil,” and for routinely snubbing the D.C. Council and, yes, unions.

The campaign seems to be in no small part prompted by anti-union comments made by Fenty at a school reform event here in Denver on Sunday. “The American Federation of Teachers, which I don’t think does anything for the people of the District of Columbia, is weighing in against it,” Fenty said, as reported in the American Prospect. “And the only thing I can think of is that the heads of the union, they want to keep their jobs.”

Fenty, the flier reads, “has become the national poster child for reforming urban schools and streamlining city government. But the image-conscious Fenty is not the reform whiz kid. Far from it.”

Joslyn Williams—-head of the Metro Washington Council AFL-CIO, which issued the flier—-was here at the breakfast this morning. Fenty was not, and has yet to appear at any official delegation events.

Nathan Saunders, general vice president of the Washington Teachers’ Union, is also here in Denver, and he says the comments Sunday were not the proximate reason for the tussle, but was prompted by his “constant behavior toward public employees.”

“This is not just the WTU,” he says. “This is every public employee union in the District of Columbia.”

Saunders says there will be no picketing of Fenty here in Denver, saying the focus will remain on Barack Obama, but, “He’s going to be unwelcome in every city he goes to this day going forward.”

UPDATE, 11:35 P.M.:: Williams confirms there’s no immediate plans to picket Fenty here in Denver—“what we’re doing is informing folks,” he says.

“The plan is to find out where he’s going to be” while campaigning for Barack Obama across the country, Williams says, and send “truth squads” of picketers to follow him.

The Fenty administration’s moves, Williams says, are “not consistent with what Barack Obama and the Democratic platform has stated.”

At-Large Councilmember Kwame R. Brown says he is surprised by the union tactics. “I’ve never seen an anti-mayor campaign during a Democratic convention,” he says. “And I’ve been to three!”

He continued, “I’m a little concerned that we’re here supporting Democratic ideals and Barack Obama, and we have anti-Fenty literature….I’m disappointed it’s come to this.”

Ward 5 Councilmember Harry Thomas Jr. echoed Brown: “It’s unfortunate that to get attention, in some ways, it had to come to this.”

LL is told Fenty will be attending the voting-rights protest at the Denver Mint, scheduled for 12:30 p.m. Eastern. More to come.

UPDATE, 1:40 P.M.: Williams estimates he’ll be distributing some 30,000 fliers here in Denver, at the Pepsi Center and elsewhere—-take that figure for what it’s worth. Fenty says of the unions’ move: “I think that’s 100 percent consistent with the 1st Amendment.”