This year’s Head’s Forum, How Did We Become So Divided?, welcomed Julian Zelizer, Princeton University political historian and New York Times best-selling author. The Head’s Forum is one of the opportunities for Grades 11 and 12 students to experience how experts in a given field grapple with ideas. Zelizer presented a keynote talk, followed by conversations with a student panel. 

His talk drew from his recent book, In Defense of Partisanship, which examines how decades of political and societal change—rooted in key moments since the 1970s—have contributed to the country’s deepening divisions.“ The question ‘How did we get so divided?’ is one people ask all the time now,” Zelizer noted. “To answer it, we need to understand our current landscape by tracing its origins.”

Zelizer identified the 1970s as a pivotal decade and outlined four major trends that have shaped today’s polarization. First, he pointed to the legacy of 1960s social movements, which challenged established norms around identity and citizenship and reshaped the national narrative. Second, he described how the evolution of media—from cable news to personal computers to social media—eroded a shared public space. With 24-hour news cycles and fewer checks on accuracy, he argued, the boundaries of factual discourse have weakened.

The third trend centered on systemic changes in interest group influence and campaign finance, which, coupled with shifts in the electorate between the 1970s and 1990s, gradually deepened partisan divides. Finally, Zelizer cited the unchecked expansion of presidential power since 1974 as another driver of institutional imbalance.

Following his keynote, students participated in a Q&A moderated by History teacher Dr. Sandra Smith. The discussion touched on a range of topics, including the intersection of technology and law, the role of international organizations, and the evolving future of American democracy.

Zelizer closed with a powerful message: “Without civic interaction, politics gets worse. It’s about creating space for dialogue—facilitating the ability to debate, discuss, and disagree in healthy ways.” Addressing the students directly, he added, “Younger generations often do what older generations could not. It’s your world that’s on the table—and yours to mold.”