This month marks the 327th anniversary of the Salem witch trials, when 19 convicted «witches» were hanged in a wave of violent persecution in Massachusetts.

Witch trials may seem like horrific events from a backwards past, but today, in many developing countries, witchcraft accusations remain common, while modern democracies struggle to balance the rule of law in the face of what seem like existential threats.

Everyone is susceptible to hysteria when fear runs rampant, and fear comes in many forms, from witchcraft to terrorism to immigration. [...]

As the jurist and demonologist Jean Bodin wrote, “Proof of such evil is so obscure and difficult that not one of a million witches would be accused and punished if regular legal procedure were followed.”

Tens of thousands of individuals were tortured, and the most common question asked by judges was “Who are the other witches?” An accusation against a single person could easily turn into a witch hunt persecuting hundreds—in the process validating public belief in the supernatural threat. Today, the excuses to weaken legal standards tend to revolve around terrorism and immigration.

A prominent example is what happened in the aftermath of the September 11 attacks.The Patriot Act explicitly weakened the rules of evidence required to pursue alleged terrorists, as well as the rules against torture. Ordinary Americans found themselves under surveillance even though the mass collection of phone records did not directly prevent any terrorist attacks, according to the government's own 2014 report. To our shame, secret prisons and torture blackened America's reputation for justice and liberty.

More recently, children as young as 4 years old have been forced to defend themselves in deportation hearings without even the benefit of counsel. Is a deportation hearing for a child so different from a witch trial?

In order to make it easier to identify and expel immigrants, the Trump administration is advocating the repeal of the 14th Amendment, which guarantees citizenship to anyone born on U.S. soil. Regardless of one's views on how many immigrants should come to the United States, this is a move to apply a different, weaker standard of law to a significant portion of the population.

Of course, present-day terrorism and immigration are real policy issues, not fantasy. However, the cost of the response depends on the perceived size of the threat.

Just as demonologists' arguments to relax standards of evidence to catch potential witches weakened the rule of law and resulted in the persecution of innocents, so do arguments to ignore or adjust the law to catch potential terrorists or immigrants.

The difficult question for citizens today is whether we are getting this balance right. We are unlikely to return to burning people at the stake, but neither America nor the world has reached the point where we can afford to forget the lessons of the witch trials.