Republican Patrick Mara on Monday endorsed his former rival, Democrat Sekou Biddle, in the April 3 Democratic primary for an at-large seat on the D.C. Council.

Patrick Mara. (Courtesy of Patrick Mara)

Biddle, who finished third behind Orange and Mara in that race, is now trying to unseat Orange as he seeks a full-term. In a statement, Mara said District voters have “but one choice in this election.”

“Ridding the D.C. Council of corruption and shady dealings by its members should be the number one thing on the minds of all voters on Election Day,” Mara said. “The quest for an honest government transcends party lines. That is why I am endorsing Sekou Biddle.”

 Doug Sloan, Orange’s campaign manager, dismissed the endorsement as being irrelevant in a Democratic primary.

“I’m sure that will get him a lot of [Democratic] primary votes,” Sloan tweeted Monday morning.

Peter Shapiro, also a candidate in the race, took a different approach and urged Mara supporters to ignore the endorsement.  

 “Reminder to folks who voted Mara,” last year, Shapiro tweeted. “You did so because you did not like Biddle/Orange last time.”

 Though Mara’s endorsement is unlikely to be a major factor in the race, it could help Biddle gain some additional traction among white voters in Northwest, which is key to his hopes of unseating Orange.

 Last year, several thousand Democrats in Northwest crossed party lines to support Mara over Orange or Biddle.

  In recent weeks, Biddle has also won the support of the Washington Post, Northwest Current and Washington City Paper, a rare trifecta in media endorsements that have large concentrations of readers in Northwest.

 But Shapiro, a former Princes George’s County Council member, landed new support Monday when Greater Greater Washington, a Web site influential with District progressives, endorsed him.  The site, which focuses on land-use and transportation issues, praised Shapiro’s record in Prince George’s County and his vision for the District.

 “Shapiro is ready and committed to bridge the gaps along D.C.'s gateway corridors, starting with Georgia Avenue, and his record more than suggests that he is fully capable of doing so,” the Web site said.

 Meanwhile, Orange has been racking up endorsements from organized labor, including SEIU-Local 7222, AFSCME, the Washington Teachers Union and the AFL-CIO. Orange’s labor support could give him an edge in turning out voters in what is expected to be a low-turnout election.