what does America represent to Amir and to Baba?

For Amir, America meant being free from a past that dominated his life. It meant respite from the guilt and regret that plagued him in Afghanistan,

"America was different. America was a river, roaring along, unmindful of the past. I could wade into this river, let my sins drown to the bottom, let the waters carry me someplace far."

For Baba, America was the opposite. No longer was he a powerful and respected man that he was in Afghanistan. In America, he works menial jobs. He feels second class and impotent. For Baba there is no trust and honour in America.