What was unique about the robbery and murder trial against sacco and vanzetti that could lead historians to classify it as a symbol of the anti-foreign feelings that arose in the 1920s?

The very interesting thing surrounding the Sacco/Vanzetti case was the fact that almost every thing brought against them was disproved by the defense. What really got them into trouble was the fact that they had been known radicals. They had the reputation of and for radical behavior. It was this radical behavior and past that was what really condemned the men. The Red Scare was at its height in 1920 when the case took place. The fear of Communists lurking around ready to take over the country was a very real fear for many Americans. Their radical past and affinity for that lifestyle and ideology is what truly convicted them. They were found guilty not for what they had done, but for what they believed. Had this case occurred a few years before or after then the 2 men would have more than likely been found not guilty of the charges. 

That is true , instead try to have a sit down talk with them