Final answer:
The Sacco-Vanzetti Trials began in 1921 and highlighted the impact of the Red Scare and anti-immigrant sentiment in the 1920s on the American justice system, leading to divisive opinions and international protests.
Step-by-step explanation:
The trial of Nicola Sacco and Bartolomeo Vanzetti, known as the Sacco-Vanzetti Trials, began in 1921 following their arrest for alleged robbery and murder. The significance of this trial lies in its historical context during the Red Scare of the 1920s, reflecting the heightened nativist sentiments and anti-immigrant bias prevalent in America at the time. Despite international protests and accusations of an unfair trial process by notable figures, including Felix Frankfurter, a Harvard Law professor who later ascended to the U.S. Supreme Court, Sacco and Vanzetti were ultimately convicted and executed. This event highlighted the rift between native-born Americans and recent immigrants, with perceptions of the trial and defendants varying greatly across different ethnic and social groups.