Imperialism - when it occurred and why

Well, Imperialism occurred at many points throughout history, mainly because of the want to acquire new territories. As to what time, I don't remember off the top of my head unless there is a specific time that you are being asked for or studying.

since most of current immigration into the u.s., both legal and illegal, is coming from latin america. it would be very difficult to imagine or rationalize a country my fellow citizens are trying desperately to flee into, would pose a threat to my prosperity or freedom. since the u.s. has a long history of intervention, but no record of permanent occupation, i would not feel oppression is the main objective.  

the largest free trade nation, along with the largest gdp in the world wanting to expand it's economic policy on us, and including us, could only be positive. the u.s. government has no interest in, or way of simply forcing american culture on us. and has no track record of it. other nations that adopted american social culture, or "americanization" did so voluntarily, mainly through the choice of allowing american businesses and u.s. citizens to come into their nations, as free operatives.

the correct option is through education. according to exodus 18, jethro advises moses to delegated some his responsibilities related to settling disputes. to effective do so, he appointed the leaders of tens, fifties, hundreds and thousands they served as teachers and advisers, as judges, and as leaders in case of war. but first, he had to teach them to perform such duties: he taught the statutes and the laws and the word of god not only to those who would hear the disputes, but also those who might dispute.