High school prom season is upon us — generally a pleasant mix of music and memories for teens, with maybe a bit of angst over getting the right date or dress.

But through the years this annual rite at times has also been an unlikely battleground over social issues, as in Mississippi recently, and over some of what the nation’s Founders called our inalienable rights — freedom of assembly and free speech.

In the 1920s and 1930s, proms as we know them began at elite Northeastern colleges, according to the Web site “Pretty for Prom” and several books and articles. In those years, proms were shaped by economic class distinctions: Kids from the wrong side of the tracks initially weren’t welcome. By World War II, prom vogue was more democratic.

A generation or two later, in the 1960s and ’70s, even though many schools and proms had been integrated for years, news accounts show that racially mixed prom couples were the stuff of controversy.

Over the last 20 years, prom night has been affected by concerns over alcohol abuse, campaigns against drunken driving, and free-speech court battles like that at an eastern Kentucky school in 2004 involving a young woman’s wish to wear a homemade prom dress styled after the Confederate battle flag.

When school officials barred her from wearing the dress, she said they had violated her freedom of speech — what’s called “expressive speech” — to proclaim her pride in her Southern heritage. “Her only dance for her senior prom was on the sidewalk to a song playing on the radio,” said her lawyer at the time. Her lawsuit was settled out of court in 2006.

The latest spat: A silk-and-chiffon hubbub that led a federal district judge to conclude on March 23 that Fulton, Miss., school officials violated the free speech of senior Constance McMillen when they canceled Itawamba Agricultural High School’s April 2 prom.

Judge Glen H. Davidson’s 12-page decision says McMillen spoke with school authorities well before the dispute became public about wanting to share the prom experience with her girlfriend and to wear a tux rather than a dress. The judge said that “Constance has been openly gay since the eighth grade and she intended to communicate a message by wearing a tuxedo and to express her identity” by going to the prom with a girl.

The court dismissed the school’s argument that it canceled the event because it would “disrupt its ability to govern local schools” and provide an education for all students. At a time when courts are more willing to support security concerns over student expression, the judge noted that even the school leaders said classrooms had been orderly throughout the controversy. And “e-mails, phone calls and other disruptions cited by Superintendent (Teresa) McNeese should not have any impact on the classroom,” the judge wrote.

In a post-Columbine, post-9/11 era, far too many courts have been willing to defer to school administrators claiming potential disruption. This ruling affirmed that students, along with the rest of us, continue to have free-speech rights.

For those concerned about “activist judges,” Davidson did refuse to go further, saying that even “the power and interests” of the federal bench “has its limits and under the circumstances, the Court cannot go into the business of planning and overseeing a prom.”

Discordant voices, on issues ranging from taxes to gay rights, from women’s suffrage to civil rights, from war and peace to immigration, have been an essential part of our democracy from the beginning of the nation.

Judge Davidson’s ruling means free expression can still triumph over what amounts to official discomfort — and over government decisions about whom we can associate with and what we can say. Even during prom season.

Gene Policinski is vice president and executive director of the First Amendment Center, 555 Pennsylvania Ave., Washington, D.C., 20001. Web: www.firstamendmentcenter.org. E-mail:gpolicinski@fac.org .