Princeton killed its 133-year honor code. AI cheating did it.

Princeton University is bringing back in-person proctored exams for the first time in 133 years. The honor code — which survived two world wars, the Great Depression, and the invention of the internet — could not survive AI.

For over a century, Princeton students pledged not to cheat and were largely left alone to prove it. That system worked until large language models made it trivially easy to produce convincing academic work on demand.

The honor is still optional. The proctors are not.