In a ruling issued Tuesday, the U.S. 9th Circuit Court of Appeals said the principal of Westview High School in San Diego and officials in Poway Unified School District have the same rights as other employers to limit speech, the Los Angeles Times reported.
"When Bradley Johnson, a high school calculus teacher, goes to work and performs the duties he is paid to perform, he speaks not as an individual, but as a public employee," Circuit Judge Richard C. Tallman wrote in the court's opinion.
The banners displayed in Johnson's classrooms included "In God We Trust," "God Bless America," and "God Shed His Grace on Thee."
Principal Dawn Kastner said the size of the banners, some as much as 7 feet wide, made them appear to promote a particular viewpoint.
The ruling reverses a decision last year by federal Judge Roger Benitez, who said the school district had violated Johnson's right to free speech.