At age 30, Simons joined the Institute for Defense Analyses (IDA), a classified NSA operation in Princeton focused on breaking Russian codes. The position offered an irresistible combination: good pay, cutting-edge work, and permission to spend half his time on pure mathematics.
During the Vietnam War, the head of IDA, General Maxwell Taylor, wrote a New York Times article defending the war. Simons, who opposed the war, wrote a letter to the Times stating that not everyone working for Taylor agreed with his views. No immediate consequences followed.
Months later, at age 29, a Newsweek stringer interviewed Simons about his anti-war stance. He explained his "policy" - until the war ended, he'd focus on mathematics rather than code-breaking work. After informing his boss about the interview, he was fired within 15 minutes on Taylor's orders. His boss wryly noted the difference between "temporary" and "permanent" members: temporary members had contracts.
The experience taught Simons about algorithms and computer modeling - knowledge that would prove invaluable decades later.