Generation independent: millennials aren't listening to you. That's a good thing.

• Author: Gillespie, Nick
• Position: Cover story

There was a moment at the 2013 Grammy Awards that captured how millennials are different than Gen Xers and baby boomers, and what it all means for the future of America. After the traditional parade of side-boob-flashing songstresses and tonsorially wackadoo manchildren allegedly flouting convention in utterly predictable ways, the hipster band fun. (whose name is uncapitalized and over-punctuated) was honored with a richly deserved statuette for the catchy generational anthem "We Are Young."

The song broke big after being featured on the hit series Glee, itself a touchstone of the millennial generation, roughly defined as those born between the beginning of the 1980s and the early '00s. Glee is set in the sort of high school unimaginable to Americans raised on older coming-of-age fare such as Happy Days, Rock and Roll High School, or even the ultra-G-rated Saved by the Bell. On Glee, even (especially!) the football players sing in a music club that features a paraplegic guitarist, a Down Syndrome cheerleader, and a lesbian Latina, an ensemble that would have been a punchline just a few decades ago. (As recently as 1983, U.S. Interior Secretary James Watt made headlines for joking that an advisory panel he appointed consisted of "a black, a woman, two Jews, and a cripple," a comment that led to his resignation.)

fun.'s "We Are Young" is a smart variation on that enduring theme of pop music, the booty call. "We are young," croons the singer to a lost or near-lost love, "So let's set the world on fire/We can burn brighter/than the sun." But then comes the generational twist: After vaguely alluding to "scarring" his lover through some unspecified failure, the protagonist sings: "If by the time the bar closes/And you feel like falling down/I'll carry you home.... I know that I'm not/ All that you got."

What matter of musical strangeness is this, actually acknowledging that your drunken, staggering bedmate could do better than you? "We Are Young" is a song in which the singer is a decent human being and penitent lover, an emotional designated driver rather than the standard-issue letch that has dominated the charts from your grandparents' "Baby It's Cold Outside" to your parents' "Under My Thumb" to the entire hair-metal genre of the '80s.

The 2013 Grammys, in contrast, were a millennial coming-out party for a different kind of POV. The post-racial, post-ethnic, post-American, post-heteronormative, post-everything likes of Rihanna and Bruno Mars and Frank Ocean and Janefle Monae and Skrillex took center stage, and the winningly metrosexual fun. took home top honors for its kinder, gentler love song.

Then came the real intergenerational shocker, when one of the members of the group thanked his parents for letting him live at home "for a very long time." Did Mick Jagger even have parents? Would Axl Rose have been able to pronounce the word mother, let alone thank her for letting him couch-surf? You could feel a half-century of rebellious rockers, from Jim Morrison to Joey Ramone, groaning in their graves.

Millennial, like F. Scott Fitzgerald's rich, are different than you and me. For one thing, at around 80 million strong, they're as big as or bigger than the baby boom--and far more populous than both Gen X (born between 1965 and 1980) and the Silent Generation (1929-1945). They are filled with what at first glance looks like contradictions: More Democratic in their voting behavior than previous generations, and yet more politically independent than any cohort in history. Worryingly unafraid of the word socialism, and yet full-bore in favor of the free market.

Understanding what millennials care about, what they believe in, and how they think is a first-order priority of anyone interested in the future of American politics, culture, and ideas. To that end, earlier this spring the Reason Foundation, with the support of the Arthur N. Rupe Foundation, conducted a national poll of nearly 2,400 18- to 29-year-olds to get a better read on this confounding cohort. Among the most important takeaways: Millennials view cultural issues as central to their identities, and they speak a distinctly different language from the tired utterances of their elders.

The Unclaimed Generation

In 2008, Barack Obama pulled an amazing 66 percent of the youth vote while his weather-beaten Republican opponent, John McCain, managed a measly 32 percent. As recently as 2000, the youth vote had been split evenly between George W. Bush and Al Gore, with each pulling slightly less than half the total. (The rest went to third-party candidates.) Democrats look at such trends and declare future elections over before they've started. And on a superficial level, why not? According to the Reason-Rupe poll, twice as many millennials--43...