One possibility, then, is that the post-’60s crime tsunami was aberrational, and the normal state of affairs is what we have now. I’m inclined to think this is the case for two reasons. First, the city’s murder rates were below 6 for nearly all of the 19th century, not just the first half of the 20th.
(There was a crime spike in the early 1860s, perhaps due to the restiveness over the Civil War draft. So maybe not all conscriptions reduce crime after all. There was another spike in the 1870s, then crime sank right up to the 1890s. (As for why violence was relatively low in late 19th century New York—a time when living conditions seemed like petri dishes for criminality—that is a mystery that continues to puzzle crime historians.)
Second, the conditions that brought on the crime tsunami of the late ’60s—the coming-of-age of the baby boomers, the mass migration of low-income African Americans among whom crime rates were high, and the caving of the criminal justice system—were unique. And while one never should say never, there’s a good chance that the perfect storm of conditions that occurred in the late ’60s will not recur. They certainly don’t seem to be in the offing any time soon. As I predicted back in 2016, when crime was rising nationwide: “We have to face occasional crime spikes or surges, such as we are now experiencing, but a long-term, sustained crime rise, on the order of those from previous eras, seems unlikely.”