What does Act 1 of All My Sons reveal about small-town society in the USA?

In Act I of Arthur Miller's All My Sons, Miller reveals his attitude towards the typical mindset of small town society in 1940s America.  The play is simply set in "the outskits of an American town" which suggests that the actions of the play could have happened in any small American town at the time.  In the first act, the audience learns that everyone in the town is privy to the trial of Joe Keller and Herbert Deever for their manufacture and sale of faulty machine parts during the war.  Although Keller was not convicted, his neighbors have made up their minds that he is guilty; they do not chastize him outright, but their negative opinion of him lingers in the background.  Keller will never be redeemed in the eyes of the town, and he will remain and be remembered as a symbol for "dirty business."  This small town mentality appears to be typical based on the manner in which Miller characterizes the setting of the play.

In Act 1 of All My Sons, what does the play reveal about small town U.S.A society?

In Act I, the reader learns that society in small town USA is tight-knit and unforgiving.  Everyone in the town knows about the trial of Joe Keller and Herbert Deever, and they also know that Keller unjustifiably escaped punishment.  When Joe was released from the trial, he decided to get out of the car at the end of the block so that everyone would see him return home.  He had hoped to convince everyone that he was indeed innocent of any role in shipping the faulty parts.  The neighbors watched him return.  They played cards with him afterwards.  They were cordial in every respect.  Yet they never gave up on their feelings that Joe was in fact guilty.  This shows that although members of society are polite on the surface, they ban together and remain unforgiving when someone is guilty.

What does All My Sons reveal about small-town American society?

Small-town America is presented in All My Sons in a rather unflattering light. Here as elsewhere in his work, Miller is challenging a long-cherished national myth; in this case, the moral purity of small-town America. The society of this small town—which could be any small town in America—is sharply judgmental. Everyone knows each other's business and feels entitled to pass judgment on what their neighbors are doing and how they live their lives.

As we might expect, the local townsfolk are none too pleased at the revelation of Joe Keller's sharp business practices. Even though Joe has not been convicted of supplying faulty machine parts to the military, he is nonetheless damned in the eyes of his neighbors. The point to make here is not that the local townsfolk are wrong in their judgment of Joe, but rather that Joe can never be redeemed in their eyes. Whatever he does for the rest of his life, he will forever be marked by corruption. This would appear to suggest that in small-town America, there is no chance of redemption.

Small Town USA is a microcosm of Big City USA.  Money is still power.  It covers a multitude of sins.

Keller is a successful manufacturer who, during the war, made faulty engine parts.  At first convicted, he was later exonerated and his partner bore the blame.  While only his partner told the truth, people believed Keller, because he had more power.  After Keller's release, they went on and socialized with him as if nothing happened.

Except that they all believed Keller to be the real guilty one.  But the court's exoneration allowed them to ignore his guilt and blame his partner. 

This explores the hypocrisy of Small Town USA.  While they decry the corruption of Big City, they themselves are guilty of the same things.

Also, in a way this play shows that all people have hidden battles.  All are in some way guilty of some type of dishonor.  We all blame it on others or on circumstances.  And the people around them will gladly accept this, if the person is someone whom they would like to socialize with.  We all make our compromises.