Why can USA citizens buy assault weapons? Who are the special interest groups who continue to block efforts to control ownership of guns in the USA? Why are assault weapons legal there?

The gun ownership and gun homicides murder map of the world

 

 Excellent resource - click on link here:

http://www.guardian.co.uk/news/datablog/interactive/2012/jul/22/gun-ownership-homicides-map 

Which countries in the world have the highest firearms murders - and the highest rates of gun ownership? Click on a country to see how it compares - and use the dropdown menu to see the map in different ways.
The Second Amendment (Amendment II) to the United States Constitution is the part of the United States Bill of Rights that protects the right of the people to keep and bear arms. It was adopted on December 15, 1791, along with the rest of the Bill of Rights.
Here is a video which shows the attitude of some gun owners who invoke their right under the Second Amendment of the US Constitution drafted in the 1700s when George Washington and others needed the citizens to arm themselves to resist the British Government during the war of independence. Yes dear readers, that is the legal basis for this poster wearing his gun on the beach and then almost taunting the police with his legal rights.

While our first thoughts and feelings go to the victims of these horrific crimes, it is legitimate to ask in a TOK context, why is the USA so different to other developed  and developing countries in this area of gun ownership? I noted on a list that that the USA has 88 guns per 100 persons in the population. Has it made them safe?