Former D.C. Mayor Adrian Fenty on Wednesday criticized the teachers striking in Chicago, instead throwing his support behind the Windy City's mayor and questioning why more Democratic mayors weren't vocally supporting Rahm Emanuel in his standoff with the teachers.

"I don't understand why people aren't rallying around him ... Kudos to Rahm Emanuel, keep it up, maybe do more," Fenty said on the Diane Rehm Show on radio station WAMU.

Chicago teachers are poised to enter the fourth day of their first strike in 25 years, after failing to reach an agreement on a new contract with city school officials after 10 months of negotiations. The key measure in the dispute is proposed changes heavily linking teacher evaluations to student test scores. Ultimately, 40 percent of a teacher's rating would be based on student achievement, and teachers could be dismissed for poor ratings.

That's a familiar song in the District, where Fenty's chancellor, Michelle Rhee, introduced an evaluation system based 50 percent on student improvement on standardized tests. Recently, the city allowed schools to scale that back to 35 percent.

While the Chicago union is estimating that 6,000 teachers could be fired under the city's proposed contract, Fenty said he saw no problem with that.

"If you start to put objective criteria in teacher evaluations and then it results in a mass layoff of teachers, then, to me, that's accountability," he said.

Tiffani Johnson, a Ward 4 parent who initially supported Fenty but says she was disappointed by his education agenda and enrolled her child in a charter school, was amused when Fenty asked why more mayors were not publicly backing Emanuel.

"He should know," Johnson said.

Mayor Vincent Gray, who unseated Fenty but has continued many of the former mayor's reforms, declined to take sides in the Chicago fight. "We think it best that the residents of Chicago be allowed to determine what's best for their city," spokesman Pedro Ribeiro said in an email.

Meanwhile, the Washington Teachers' Union called on D.C. teachers to wear red to work in support of the Chicago teachers.

"I'm disappointed that former Mayor Adrian Fenty still has not learned," said union President Nathan Saunders, referring to Fenty and Rhee's brusque style in communicating their reforms. "It certainly brought in a new mayor, a new chancellor and a new teachers union president. That's not by accident."