If you wanted to build a wall a hundred years ago, it would have had to be on the Atlantic.

I’ll be speaking on my novel “Suosso’s Lane” at Duxbury Library on Sunday, Jan. 29, 2 p.m., my first opportunity following the inauguration of a new administration to address the potential lessons for our own time from the notorious Sacco and Vanzetti case, in which two Italian immigrants were convicted of murder in 1920 after a biased trial offering absurdly thin evidence of their guilt. Comparisons between where we are today and the state of American society and politics a hundred years ago give me a thematic subtitle for Sunday’s talk: “Sacco and Vanzetti, Democratic Stress Tests, and Dangerous Times.”

I believe there are lessons for our own time from a consideration of the social, political an economic conditions that form the background for the Sacco-Vanzetti, in which (from the evidence we do have) it appears that prosecutors invented a theory for who committed a payroll robbery and killed two officials that fit nicely into contemporary hysterical fantasies about the dangers posed to the nation by — in 1920 — foreign anarchists. And then picked out two “perpetrators” who fit the bill and went about inventing case against them that relied on current-day prejudices to win a conviction from a jury already persuaded that foreign radicals were capable of any horrendous crime you could imagine.

Where did these dangerous foreigners come from? The other side of the Atlantic. Largely from southern and eastern Europe. More from Italy than anywhere else.

Comparisons between that time and our own seem especially worth examining now that we are a week into a new administration that plans to build a border wall, reduce legal immigration and otherwise turn its back on traditional American democratic and egalitarian values, much like the period in which Sacco and Vanzetti were executed because of their beliefs and their ethnicity.

A time of “us” and “them.”

One of those times, Sacco and Vanzetti’s time, was called the “Red Scare.”

Every historical source that discusses Sacco-Vanzetti mentions the “Red Scare” as the essential piece of background to understand the famous case. In his book “Sacco and Vanzetti: the Anarchist Background,” historian Paul Avrich writes, “The trial, occurring in the wake of the Red Scare took place in an atmosphere of intense hostility towards the defendants.”

My one-sentence definition is the Red Scare was period of social unrest and hard times set ablaze by anarchist bombings that led in turn to a massive, extra-legal crackdown on ‘radical’ immigrants and deportations in 1919-20.

Like the era that produced it, the Sacco-Vanzetti case appears to shine a light on the darker side of American society’s historical treatment of immigrants of ‘unfamiliar’ ethnicity. Periodically — especially in those periods when a ‘new’ group of foreign nationals arrives in large numbers — the so-called ‘nation of immigrants’ has exhibited a desire to close doors and build walls. Forgetful of their own non-native origins, many Americans are quick to close the borders on the next group of newcomers, whose language or manners, or religion, or skin tone, or potential for economic competition, or imagined demand for public services, is said to threaten the well-being of those already comfortably settled in the United States. In the first two decades of the twentieth century, it was the turn of Italians to be the most numerous and visible of these presumed-to-be-problematic newcomers.

The lessons of the Sacco-Vanzetti case may still be staring us in the face, especially at a time when many countries in both the new and the old worlds are experiencing crises over the arrival of large numbers of ‘others’ within settled, comfortable, more ethnically homogeneous borders.

For more on the Red Scare, see my blog http://prosegarden.blogspot.com/2017/01/the-garden-of-history-what-we-can-learn.html