It was the second night of Hanukka in New York, and I was celebrating along with many young American Jews my age at a concert starring Matisyahu, a Hasidic reggae rocker who borrows lyrics from the Tanakh. I’m no Matisyahu devotee: My husband bought the tickets and I went reluctantly, expecting a small venue with a few diehards in dreadlocks. To my surprise, I found myself in an enormous sold-out hall filled with over a thousand ecstatic fans, nearly all of them young American Jews. These concertgoers sang along with the brakhot when Matisyahu lit a giant hanukkiyaonstage.

The scene was admittedly surreal. But the strangest aspect was the realization that no one in my parents’ generation would have been caught dead at a concert where the star had payes. And what is even stranger is that despite the old dire predictions about vanishing American Jews, we are now on the edge of an American Jewish renaissance, one where Matisyahu barely qualifies as a novelty and where every day brings another Web site, magazine, anthology, band, gallery show, congregation, political organization or social event created by innovators in their twenties and thirties who are reinventing American Judaism itself.

It isn’t Matisyahu who tells us this as much as his fans. The 2000 National Jewish Population Survey, which had mistakenly claimed a population decline, has now determined that our population has grown—not merely in quantity, but in inventiveness and passion. Thirty years ago, the way young Jews asserted their independence was to marry someone non-Jewish and eat on Yom Kippur. Today, the way to rebel is to go to Chabad, or show up for Matisyahu or anything else in the vast array of cultural choices created by and for young American Jews.

How did this happen? america has changed; ethnic identity is “hip.” But something else is at work here, too. For young Jewish adults, the formative public event in our lifetime has been 9/11—and we perceived this horror differently than other Americans did. The seemingly endless terrorism in Israel made it clear that rising global hatred threatened some infidels more than others, and synagogues—not churches—erected concrete security barriers. These same young people then went to college to be met with divestment petitions against Israel, furious anti-Israel rallies and respected intellectuals making inflammatory statements about Jews that were once the province of kooks. They watched as their own classmates eagerly signed on. While teaching Jewish studies college courses during the past five years, I noticed how Jewish students, many of them previously uninvolved in Jewish life, gravitated to my classes, seeking a kind of solace that students 10 years earlier wouldn’t have needed. They saw that their own future was at stake.

At one national turning point past, the prophet Joel (3:1) imagined a day when “your sons and daughters will prophesy; your old men shall dream dreams and your youth shall see visions.” Today we are a people in need of vision. Not the kind of vision that our parents’ generation needed, as they tried to rescue a community slated to assimilate itself to death, but a grander vision, one that addresses the reality that we are now, as always, a people that must continuously assert its right to exist—and, more positively, its right to determine all possible approaches to that existence. What I can report to you, from the ranks of those young American Jews who have grown up knowing not to take this existence for granted, is that we are already working on it.

Dara Horn’s most recent novel is the award-winning The World to Come (W.W. Norton).