In 1692, nineteen people hanged in Salem for witchcraft. In 1953, Julius and Ethel Rosenberg were executed as Soviet spies. Different centuries, different fears, but the social machinery that condemned them operated with striking similarity. From medieval Europe to McCarthy's America, from Stalin's purges to social media cancellations, societies experiencing stress follow a predictable script when hunting their supposed internal enemies.

These moral panics aren't random eruptions of madness. They're structured social phenomena that emerge when communities face genuine threats they can't control. Understanding their patterns helps us recognize when our own society might be sliding toward similar dynamics—and perhaps more importantly, why even rational people get swept into irrational crusades.

The Salem witch trials didn't begin with superstition—they began with war, disease, and economic collapse. King Philip's War had devastated New England, killing one in ten colonists. Smallpox ravaged communities. Trade disputes threatened livelihoods. When societies face overwhelming external threats they can't defeat, they often turn inward, seeking enemies they can control.

McCarthyism followed the same pattern. America had just discovered Soviet spies had stolen atomic secrets. China had fallen to communism. The Korean War was going badly. Americans felt surrounded by an invisible enemy they couldn't directly fight. So they fought the enemy they could reach—their neighbors, coworkers, and fellow citizens suspected of communist sympathies.

This displacement serves a psychological function. Fighting witches or communists gives communities a sense of agency when facing uncontrollable threats. The French Revolution's Terror emerged during foreign invasion. Stalin's purges intensified as industrialization disrupted traditional life. When people can't fight the real source of their anxiety, they create enemies they can defeat, transforming helplessness into action, even if that action is ultimately self-destructive.

Once witch hunts begin, they follow a terrifyingly predictable acceleration pattern. In Salem, the first accusations targeted social outcasts—a Caribbean slave, a poor woman, a contentious neighbor. But within weeks, accusations spread to respected church members and eventually the governor's own wife. This wasn't unique to Salem; it's how denunciation dynamics always evolve.

The mechanism is simple but powerful. Once authorities validate the first accusations by arresting suspects, they create immediate incentives for more accusations. In Salem, confessed witches who named others avoided execution. During McCarthyism, former communists who identified fellow travelers received immunity. Stalin's show trials offered reduced sentences for those who implicated others. Each system rewards denunciation while punishing silence.

Social proof amplifies these incentives. When neighbors see accusations being taken seriously, staying silent becomes suspicious. Not denouncing someone might suggest you're protecting them—or that you're one of them. Medieval inquisitions called this 'negative evidence.' McCarthy's committee considered refusing to name names as proof of communist sympathy. The safest position becomes enthusiastic participation. Yesterday's skeptics become today's most zealous hunters, not from belief but from self-preservation.

Witch hunts end as suddenly as they begin, and usually for the same reason: they reach too high. Salem's trials collapsed when accusers named the governor's wife and other colonial elites. The governor immediately disbanded the special court, declared spectral evidence invalid, and pardoned the accused. What had been urgent moral necessity became embarrassing excess virtually overnight.

McCarthy's crusade followed an identical arc. He remained powerful while targeting Hollywood writers and State Department employees. But when he attacked the U.S. Army and suggested President Eisenhower harbored communists, the establishment turned on him. Within months, the Senate censured him. The same colleagues who had enabled his investigations suddenly discovered their courage.

This pattern appears throughout history because witch hunts rely on elite endorsement for legitimacy. Elites initially support or tolerate these campaigns because they seem to target 'others'—the poor, minorities, intellectuals, or political opponents. But accusation dynamics inevitably expand upward. When elites realize the monster they've fed might devour them, they swiftly dismantle the very machinery they helped create. The French Terror ended when Robespierre threatened his fellow revolutionaries. Stalin's purges slowed when he'd eliminated so many officials that government couldn't function.

The script of witch hunts remains remarkably consistent across centuries because it exploits fundamental patterns in human social psychology. Genuine external threats create anxiety. That anxiety seeks accessible targets. Accusation dynamics reward participation and punish restraint. The cycle continues until it threatens those with power to end it.

Recognizing these patterns doesn't make us immune to them. The Salem judges were educated men who knew about false confessions. McCarthy's era included sophisticated people who understood propaganda. Today's moral panics involve participants who've studied these exact historical examples. Knowledge helps, but when the social machinery of denunciation starts turning, standing outside it requires extraordinary courage that few possess until the danger has passed.