Racial tensions and gang problems were plaguing a Northern California high school when three students arrived for classes in 2010 wearing American flag T-shirts on Cinco de Mayo.

Unpleasant verbal exchanges and altercations marked the previous year's Cinco de Mayo celebrations at Live Oak High School in Morgan Hill, 20 miles south of San Jose. So when students told administrators that trouble was a possibility because of the American flag attire, the students were ordered to turn their shirts inside out or go home.

They went home, and the incident sparked a national debate, prompting satellite news trucks to camp outside the school for several days afterward as well-known pundits across the political spectrum argued about the issue over the airwaves. Cinco de Mayo is observed by some as a celebration of Mexican heritage.

The three students have since graduated, but a federal appeals court in San Francisco on Thursday will consider their lawsuit alleging the school violated their free speech and equal protections rights guaranteed by the U.S. Constitution. The three-judge panel of the 9th U.S. Circuit Court of Appeals is not expected to rule Thursday.

A lower court tossed out the students' lawsuit in December 2011, ruling that school administrators have wide legal latitude to ensure the safety and effective operation of their campuses and a "perceived threat" of violence vindicated the principal's decision.