It’s long been known that the only acceptable form of sexism in the politically correct world is that from liberals against those women they disagree with.

Take Campbell Brown, an education advocate fighting for school choice who wants to challenge teacher tenure.

Despite Brown’s long career as a journalist and the fact that she donates exclusively to Democrats, teachers unions are trying to brand her a “right-wing elitist.” They base this on the fact that Brown recently registered as a Republican to vote in a New York primary.

The thing is, Brown is currently not registered to any party.

In her latest column for USA Today, Fox News contributor and Daily Beast columnist Kirsten Powers (a former Democratic strategist) noted the sexism being directed at Brown by the teachers unions, who are still clinging to tenure.

“For this, [Brown] has been on the receiving end of a sexist assault by the American Federation of Teachers and opponents of education reform,” Powers wrote. “AFT President Randi Weingarten took to Twitter to accuse Brown of not being balanced in her approach to school reform because ‘she's married to Romney adviser Dan Senor.’

“To Weingarten, women are not people with thoughts of their own,” Powers added. “No, they're empty vessels who do their husband's bidding.”

Here’s the tweet Powers mentions above along with Brown’s response:

And that’s not the only attack Brown has received. In July, former assistant education secretary Diane Ravitch wrote that Brown doesn’t know what she’s talking about on education and is basically only listened to because she’s attractive.

“She is a good media figure because of her looks, but she doesn’t seem to know or understand anything about teaching and why tenure matters,” Ravitch said. “I know it sounds sexist to say that she is pretty, but that makes her telegenic, even if what she has to say is total nonsense.”

As Powers notes, that “nonsense” is also embraced by former White House Press Secretary Robert Gibbs (under President Obama), former Obama campaign press secretary Ben LaBolt and Al Gore’s lawyer in Bush v. Gore, David Boies.

You know, those right-wing elitists.