Kagan attended Hunter College High School, where her mother taught. The school had a reputation as one of the most elite learning institutions for high school girls and attracted students from all over New York City. Kagan emerged as one of the school's more outstanding students. She was elected president of the student government and served on a student-faculty consultative committee. Kagan then attended Princeton University, graduating in 1981 with a Bachelor of Arts summa cum laude in history. She was particularly drawn to American history and archival research. She wrote a senior thesis under historian Sean Wilentz titled "To the Final Conflict: Socialism in New York City, 1900–1933". In it she wrote, "Through its own internal feuding, then, the SP [Socialist Party] exhausted itself forever. The story is a sad but also a chastening one for those who, more than half a century after socialism's decline, still wish to change America." Wilentz says Kagan did not mean to defend socialism, noting that she "was interested in it. To study something is not to endorse it."
