Cross-posted from the Washington Post By Aaron C. Davis and Emma Brown

D.C. Mayor Vincent C. Gray (D) chose a debate on education Monday night to make his campaign debut alongside council members, a restaurant owner, a former State Department official and others trying to keep him from a second term.

He could have picked an easier place to start.

Before a packed auditorium at Eastern High School of teachers, union leaders and activists — many of them upset with Gray’s current schools chancellor, Kaya Henderson — Gray was welcomed with a question that immediately put him on the defensive.“What is your criteria for selecting a chancellor?” asked President Elizabeth Davis of the Washington Teachers’ Union, which sponsored the forum.“Our chancellor is a person who understands the importance of working with teachers,” Gray began, eliciting a smattering of boos and groans.“She was the first appointment that was made in my administration.” More groans.As Gray got around to the heart of his response, the bell rang and he was cut off.“When you look at the results, our test scores have gone up . . . .”

Gray’s voice trailed off. He set down the microphone and returned to his seat.

It was as good as it got for the rest of the night.

The hostile crowd showed that the city’s long-beleaguered school system — and tense negotiations with its teachers union — could complicate the incumbent mayor’s reelection narrative that the city’s schools have improved under his watch.

During Gray’s three years in office, the District’s public school system has recorded rising scores on standardized testing, and Gray has highlighted those achievements as evidence of his seriousness about education reform. He would continue on that path if reelected, he said.

But in holding up test scores as the barometer of success, Gray has exposed himself to the charge that he has abandoned his skepticism of reform from his 2010 campaign. Then, he said test scores were not the largest measure of success — helping to attract the strong backing of the Washington Teachers’ Union.

On Monday, upstart candidates including restaurateur Andy Shallal, the owner of Busboys and Poets, and Reta Jo Lewis, a Democrat and former State Department official, drew the biggest applause, indicting both Gray and members of the council who seek to replace him for alienating parents and teachers amid a forceful push for school reform.

Shallal criticized mayoral control of the schools, which was authorized in 2007, saying that it has led to untenably high teacher turnover and “changed the way we put the public in public schools — people have become more disenfranchised, disaffected and disrespected.”

He also took aim at the city’s support for school choice, in which many children face long odds to win admission by lottery to the most sought-after schools.

“I don’t want to play Russian roulette with our kids,” he said. “Every single kid deserves a good education.”

Lewis drew hoots of support when she declared that, since the D.C. Council granted then-Mayor Adrian M. Fenty power to take over the ailing school system, too many “secrets” have been kept about school management.