A former Bucks County high school teacher who was fired after profanely blogging about her "utterly loathsome" and "frightfully dim" students cannot sue the Central Bucks School District for violating her right to free speech, a federal appeals court ruled Friday.

In a split decision, the U.S. Court of Appeals for the Third Circuit ruled that the disruption that Natalie Munroe caused at school with her online writings outweighed her claim that the First Amendment should have protected her from losing her job.

"When a teacher's derogatory comments about his or her students cause numerous parents to tell the school district that they 'don't want her as my child's teacher,' it is appropriate to conclude that his or her speech impedes the performance of the speaker's duties as a teacher," wrote Judge Robert Cowen.

The 2-1 decision affirms a judgment made last year by District Judge Cynthia Rufe.

Munroe, who taught English at Central Bucks High School East, could not be reached for comment Friday.

But her attorney, Steve Rovner, said Friday that they plan to appeal the decision by asking the entire Third Circuit bench to review the case.

"It's an important constitutional issue," he said. "And we believe in Ms. Munroe's rights."

Munroe drew national attention in 2011 when it was discovered that she had written a blog describing her students as "ratlike," "lazy," and "the devil's spawn," to name a few examples.

Munroe blogged under the name "Natalie M." and had intended that the website remain anonymous. But a student discovered it and shared it on social media.

When the story spread, court filings say, Munroe defended herself in various national media outlets.

She was initially suspended by the district, and in 2012 she was fired.

She then sued the district for violating her right to free speech, arguing that because she wrote the blog as a private citizen, the district should not be able to fire her for it.

Eugene Volokh, a law professor at the University of California, Los Angeles, who specializes in First Amendment issues, said that argument has been made in similar cases for many years.

The issue, he said, is that government employers - such as school districts or police departments - should be able to decide at some point that an employee has become too big a distraction to continue in the position.

"Why should we be paying taxpayer money to hire somebody when they are undermining the job they are asked to do?" he said.

The difficult question is in determining - and proving - when an employee's disruptions have gone too far, he said.

In Munroe's case, the appeals court pointed to language on her blog that it called "despicable." Although she never named individual students in her writings, the court said that parents could easily identify specific children due to the details she provided.

The court also said the district eventually allowed students to opt out of Munroe's classes and assigned a "shadow" staff member to help reduce the distraction around her.

Combined, the court ruled, those disruptions nullified her right to keep her job.

"The First Amendment does not require a school district to continue to employ a teacher who expresses the kind of hostility and disgust against her students that Munroe did on her blog and then publicly defends such comments to the media," Cowen wrote.