Gov. Christie continued to wage verbal war against teachers' unions at an education forum in New Hampshire on Wednesday, saying the unions deserved a "political punch in the face."

The word political was a qualification to the sentiment Christie expressed in an interview this month with CNN's Jake Tapper - spurring the president of the American Federation of Teachers, Randi Weingarten, to accuse Christie of promoting "a culture of violence."

But while he framed his attack slightly differently, Christie didn't soften his combative tone Wednesday.

"They're punching us all the time," he said at the forum, which was streamed online and held by the Seventy Four, a nonprofit news and advocacy site that says it aims to "challenge the status quo" in education.

The forum, in a Londonderry, N.H., high school, was led by Campbell Brown, a former CNN anchor and founder of the news site, who interviewed a half-dozen of the GOP presidential candidates, one by one.

"My point I was making in that interview with Jake is, they deserve it back," Christie said to Brown.

Calling for a "fundamental fight" against teachers' unions, he said the unions "and the educational establishment" resist changes because fixes to achievement gaps "take apart the monopoly they have on education."

Among the GOP candidates at the event were former Florida Gov. Jeb Bush, who has been a supporter of the Common Core educational standards, unpopular with many conservatives.

Christie, who has walked back his support for the standards, embraced his backtracking Wednesday, saying he reacted after listening to his constituents.

"I actually have a thinking, operating brain," Christie said.

Christie's change of heart on the standards may have prompted a big New Jersey donor, billionaire hedge-fund manager and education reform advocate David Tepper, to join Bush's camp, according to the Bergen Record.

The newspaper, citing unnamed people familiar with Bush's efforts, claimed Sunday that Tepper was swayed to Bush in part because of Christie's withdrawal of support for Common Core.

A message for Tepper - who in May gave $250,000 to a super PAC supporting Bush - went unreturned Wednesday.

At the forum, Christie went after Bush, who earlier in the day said that he would hope to work with Weingarten, but that she was "not going to change," according to the Associated Press.

Christie - who reached a deal with Weingarten in 2012 to provide merit pay for Newark teachers, with money donated to the school district by Facebook founder Mark Zuckerberg - accused Bush of "admitting to failure."

"Abandoning the idea of working with this problem isn't what an elected official does," Christie said.

In a tweet Wednesday, Weingarten responded: "Sad state of affairs when one of the only GOPers willing to talk about listening to teachers also wants to punch us in the face."

During his remarks, Christie voiced his opposition to teacher tenure protections, which he said stood in the way of accountability. Parents, he said, can answer the question of "good teacher or bad teacher" after spending 10 minutes at a back-to-school night.

"You do not need a Ph.D. in education to understand this," Christie said.

Christie also on Wednesday talked up changes to the education system in Camden, citing charter and Renaissance schools and reductions in school district staff. He praised Superintendent Paymon Rouhanifard, who was installed after the state took over the school district in 2013.

Christie said Camden was benefiting from "the combination of a cooperative political group down in Camden and an activist, educational governor."

The governor has found allies in key South Jersey Democratic leaders, including power broker George E. Norcross III.