In the criminal law system of the United States and most democratic nations, innocence is simply regarded as the absence of guilt. It is considered the condition in which all the citizens of our civilization exist while going about their day to day lives, in harmony with the customs and values of their society, blameless in the eyes of the law.
When criminal charges are brought against a person in the United States, he is being accused of some act or omission that conflicts with the laws and customs of his society and his innocence comes under question. The presumption of innocence is an essential principle in the U.S. criminal law system that obliges the arbiters of justice to lean heavily in favor of the accused, and places the burden of proof on the government to demonstrate beyond a reasonable doubt that the defendant is not innocent, but in fact is guilty of a crime. Criminal guilt connotes an injury that has been done to society as a whole, and so a guilty party will receive punishment from society as a whole, through fines, incarceration or both.
The defendant has the right to a legal attorney and trial by an impartial jury in the defense of his innocence. The adversarial legal system of the U.S. provides ample opportunity for the defendant's innocence to be argued and demonstrated in court by means of evidence and testimony by witnesses of the defense's choosing. If the prosecution cannot produce enough evidence to prove the defendant's guilt beyond a reasonable doubt, then the defendant is found not guilty, his innocence is maintained and he is free to go.