USA should have taken from Britishers some lessons in Colonialism and Imperialism . In India after defeating the Sikhs and Gurkhas Britishers did not destroy them .Instead Britishers cultivated them as friends and allies . They were great help in the Imperial designs. But USA has proven to be a very poor Imperialist.
Earlier USA should not have invaded Iraq. No Weapons of Mass Destruction ( WMD ) were ever discovered in Iraq.