Final answer:
The correct answer of Sacco and Vanzetti trial - increased concerns about communist influence in the United States, spotlighting the influence of the Red Scare and intensifying fears of radical political movements.
Step-by-step explanation:
An effect of the Sacco and Vanzetti trial was that it increased concerns about communist influence in the United States. The trial of these two Italian immigrants, who were anarchists, shifted the public focus onto their political beliefs rather than the actual evidence of the crimes they were accused of. The trial took place during a time of heightened fear of anarchism and communism, known as the Red Scare, and their execution only served to intensify those fears.
Both Nicola Sacco and Bartolomeo Vanzetti were known anarchists who supported anti-capitalist revolution through violent methods. Their trial underlined the national anxieties about radical political movements and the potential threat they posed to American society. As a result of their executions and the questionable judicial process, it renewed scrutiny of the U.S. justice system, particularly regarding whether individuals were being tried for their actions or their political and ethnic backgrounds.