Mayor Vince Gray's endorsement of Sekou Biddle in the race to permanently fill an at-large D.C. Council seat has effectively narrowed the field to two main candidates as the debate becomes a battle over who can best claim the Michelle Rhee title of school reformer. Gray's endorsement comes with the heavy weight of a political machine that has gathered little dust since Gray ousted Mayor Adrian Fenty in September's Democratic primary. Biddle also has the advantage of holding the seat on an interim basis after winning a close vote by the D.C. Democratic State Committee earlier this month. That leaves the remaining dozen Democratic candidates as outsiders looking in, and puts the only Republican in the race, Patrick Mara, in the position as Biddle's main challenger in the April special election.

"Gray's endorsement of Sekou Biddle certifies him as the Democratic candidate to beat," said political consultant Terry Lynch. But "most political action has the equal and opposite reaction ... it may help Biddle, but it may potentially hurt Biddle."

The thrust of Biddle's campaign is that he's an education reformer cast in the image of former D.C. Schools Chancellor Rhee, who has become a national advocate of school reform. Biddle endorsed Fenty in the primary, when Biddle was still representing Ward 4 on the board of education. He has been working on education reform for 17 years, Biddle told The Washington Examiner on Friday, the day after Gray's endorsement.

"I am these people," he said of his connection to Rhee and Fenty. "I am in the whole entirely with education reform."

But now that he has Gray's backing, Biddle has opened himself up to attacks from Mara, who also is positioning himself as an education reformer ready to fill Rhee's philosophical shoes.

Mara was quick to point out to The Examiner on Friday that Gray already has begun to back away from the teacher evaluation testing, IMPACT, that was a centerpiece to the reforms Rhee instituted. Potential rollbacks of those reforms under a Gray administration was the main thrust of Fenty's re-election campaign.

"By aligning himself with people who are not from the Rhee camp, I don't see how Biddle can still be independent," Mara said. "There's no way he can claim the Rhee mantle anymore."

Meanwhile, Vincent Orange, who once considered himself the front-runner for the Democratic State Committee's vote before Biddle swept in, is now casting himself as David against Biddle's Goliath.

"Clearly I'm the outsider," Orange said. "But we still need a strong independent voice on the council."