"Saturday Night Fever," the film that launched John Travolta to superstardom and made the Bee Gees cool will be 30 years old this month.

The movie still holds a memorable, if slightly ridiculous, place in the history of American pop culture. The image of Travolta disco dancing in white polyester instantly summons up the senseless hedonism and supposed cultural bankruptcy of the 1970s.

But the movie isn't an artifact of a (thankfully) bygone era. It's as relevant as ever. "Saturday Night Fever" sketched a dark, serious portrait of American life. Its poignant depiction of young working-class ethnics, determined to dance themselves out of dead-end jobs, uncannily echoes conditions that spawned today's "American Idol," "America's Got Talent" and "So You Think You Can Dance."

Lapels aside, the film seems strangely prescient -- a road map to the income inequality, the ethnic and racial politics, and the lure of celebrity that we see today. Culturally speaking, the '70s are back. As we grapple with soaring gasoline prices, tune in to "Dancing With the Stars" and work through a new kind of national malaise, we would do well to heed the cautionary lessons of the young man in polyester.

The economic downturn of the Carter years loomed large in the home of Travolta's character, Tony Manero, in Brooklyn. Tony works a dead-end job in a paint store. On Saturday night, he begs his boss for an advance to buy a "beautiful shirt" before returning home for a family supper. After 20 years of steady construction work, Dad has lost his job and his authority in the household. Tony's mother has defiantly bought pork chops even though the family cannot keep up with the rising price of meat.

The hardships of the 1970s reversed a long period of economic expansion and upward mobility. After World War II, the postwar boom lifted millions of working Americans into a comfortable middle-class lifestyle. Union jobs, cheap federal mortgages and guaranteed student loans made it possible for blue-collar families like the Maneros to purchase their piece of the American dream. Between 1947 and 1968, the disparities between rich and poor actually declined.

Many Americans started to lose their economic foothold in the 1970s, and the booms and busts of subsequent decades have only made things worse. Since 1968, the richest 20 percent of the population has amassed an increasing share of national wealth. U.S. manufacturing jobs that once provided secure, high-paying employment for blue-collar workers like Tony's father began to vanish. Today's working families face dire straits similar to those of the '70s.

"Saturday Night Fever" also revealed a simmering ethnic conflict. Amid clashes over school busing and integration, the American melting pot gave way, with many racial minorities embracing cultural nationalism and ethnic whites experiencing a revival of cultural awareness. In 1970, the future Sen. Barbara Mikulski, then a young Baltimore politician, warned in the New York Times: "The ethnic American feels unappreciated for the contribution he makes to society. In many ways he is treated like the machine he operates or the pencil he pushes."

The movie faithfully evoked -- and criticized -- this hypersensitive brand of ethnic identity. Tony and his friends avenge the beating of one of their buddies in what they proudly declare "true Italian style": They attack a Puerto Rican club in a nearby neighborhood (calling Puerto Ricans "crab lice"), severely injuring their rivals and nearly ending up dead themselves. The next morning, they realize they may have attacked the wrong group.

As the camera lingers on the teenagers' blank, disgusted faces, the film makes us wonder about a national culture in which racial prejudice trumps community. The movie subtly skewers those who would pursue narrow, self-serving objectives by exploiting ethnic antagonism -- a lesson as true today as in 1977.

Most pointedly, the film anticipated today's crazed celebrity culture. In "Saturday Night Fever," disco dancing is an escape, an exit from a bleak world of stifling families, pinched circumstances and decaying neighborhoods. For Tony, neither education nor work can punch his ticket out of Brooklyn, out of poverty, out of boredom and violence and degradation. Only by winning a dance contest, by grabbing momentary fame, could a working-class, outer-borough Italian aspire to the affluence, glamour and polish of WASP Manhattan.

Tony could never have imagined the world of reality television, when the local dance contest or the neighborhood talent show becomes a nationally televised event. In "Saturday Night Fever," the dance ticket is the only passport out of drudgery. Only stardust, like that sprinkled by "American Idol" and its imitators, can rip the unfortunate from endless woe (and leave the rest behind). "Where do you go," the movie's publicity posters asked, "when the record is over?"

Three decades later, even Tony's prized coiffure ("Would you just watch the hair?" he tells his father. "I work a long time on my hair, and you hit it!") has become an often-mocked symbol.

But this strangely serious film turns out to have anticipated some of our current predicament. "Life goin' nowhere," moaned the Bee Gees in "Stayin' Alive," the film's signature song. "Somebody help me."

Schulman is professor of history at Boston University.

(Dec. 5, 2007)