Ward 3 Councilmember Mary Cheh announced today on TBD’s Newstalk with Bruce DePuyt that she is supporting D.C. Council Chairman Vincent Gray in his bid for mayor.

Cheh represents the white, affluent ward in which Mayor Adrian Fenty will need to win approximately 134 percent of the vote in order to offset the gains Gray will make in other parts of the city. So this doesn’t exactly help. And a video message Cheh recorded on Gray’s behalf effectively robs Fenty of the one argument he was hoping to woo wealthy white voters over with. “We might never have had school reform if it wasn’t for Vince Gray,” Cheh says. “He’s the one that brought everyone together to make sure the legislation was passed. As Mayor, he will lead that reform forward.”

Fenty is well-liked in Ward 3, in large part for his support for Schools Chancellor Michelle Rhee. But his relationship with Cheh has long been strained. Here’s an excerpt from LL’s cover story on Fenty’s personality:

Cheh, who joined the council at the same time Fenty became mayor, says she had high expectations for working with the young chief executive. And, she says, those hopes were quickly dashed after he made it clear that he expected a quid pro quo type of relationship, where she would support him from the council in return for favors in her ward.

Now, she says, Fenty doesn’t even extend the most routine of political courtesies, like inviting her to ribbon cuttings in her ward. “He’s his own worst enemy,” Cheh says, going a little over the top by comparing Fenty to a “Shakespearean” tragedy. “The idea that you have such promise, you had such potential, you had all that wind at your back and yet because of your own internal failings you squandered it.”

On Newstalk, Cheh said she was “very pleased” with the Washington Post‘s recent poll that shows Gray the likely winner in the race. She said she was orginally skeptical of Gray when she joined the council four years ago, but said he’s a “man of integrity” and has won her over. “Having worked with him over the last four year shoulder to shoulder,” Cheh said.  “I have become an admirer.”

She added that it’s a “deep disappointment” that she and Fenty didn’t work well together, and said the good work he’s done is “not enough” to outweigh his autocratic, secretive style.

“Instead of opening the door, the door is shut,” she said of Fenty.

Gray campaign aides say the two of them will appear together in Tenleytown this afternoon.

So what does it all mean? The power of endorsements is always a tricky thing to measure. It’s possible Cheh will push some tentative Gray supporters, still uneasy about whether he’s committed to school reforms, into a solid vote, or persuade some Fenty voters to take a second look at Gray.

But the endorsement may be more interesting as a sign of where the campaign stands. Fenty is still popular among Cheh’s constituents, and she does have a Republican opponent this fall, Dave Hedgepeth. Endorsing Gray is a pretty clear sign that Cheh isn’t worried about a backlash against her from Fenty’s base in her ward. Less than two weeks from the election, Fenty’s political capital is dwindling fast. (While Cheh endorsed Gray this morning, Fenty trumpeted an endorsement from… the Deauville Apartments tenants’ association, which was hardly a surprise, as the Mt. Pleasant Street NW apartment building has been plastered with Fenty signs for weeks.) If he couldn’t even keep Cheh neutral, he’s in bad shape, indeed.

Photo by Darrow Montgomery