I didn’t mention the drug war because it doesn’t explain the increase in crime rate—it’s about a decade too late. The increase in violent crime actually began in the 1960s. By the time the DEA was created in 1973, violent crime had more than doubled since 1963. It then actually slowed down a bit—it increased only another 50% from 1973-1983. By the start of Reagan’s term in office, violent crime was already near peak levels. (It would increase about another 1/3 before peaking in the early 1990s.)

Vietnam is one possible explanation, having started in 1955. I have never seen any analysis of that. But unlike the drug war, at least the timing works out.