America in South Korea and The Middle-East

I had the chance to ask some Korean citizens if Koreans still see America as a positive global force. It seems like many Koreans were disappointed in America during the Bush era, but they still view America is a very positive presence. So, a thesis I would like to look into is, why does America’s presence in South Korea mostly seem like a success while America’s time in the Middle-East mostly a failure? What did we do differently? Or is the problem that we went into two very different areas with the same approach? Are there any books or good launching points you guys can suggest? Please and thank you.