There is a book called "Overthrow : America's Century of Regime Change from Hawaii to Iraq".  It talks about 14 cases when the US became involved in another country. ie) panama, nicaragua, hawaii, iraq, iran, cuba, and more. The author was a foreign correspondent for the New York Times and says how the countries where the US became involved in, were worse off than before the Us became involved.  He also says that the US becomes involved in other countries basically to protect US international business.  ITs a great read.