Right to bear arms - Lets question - Why do we need to

Right to Bear Arms
In wake of today's shootings Lets question ourselves
Why do we need to have the RIGHT TO BEAR ARMS
http://www.cnn.com/2009/CRIME/04/03/binghamton.shooting/index.html

Coming from a country of a billion+ people where right to bearing fire arms is very restricted privilege, i was first struck in dismay the ease in which any one can buy a gun in America

Who gives this undeniable right to bear arms that cannot be taken away ?

Amendment 2 of the US constitution Right to Bear Arms.
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed

I get the right the thought behind it etc
But this was ratified in 1791, we have come a long way from then where we have structured police force, army, reserves, FBI, Neighbourhood watches etc to guard and protect us.
The primary interpretation of the Amendment is disputed,
http://en.wikipedia.org/wiki/Second_Amendment_to_the_United_States_Constitution
Wiki says the neutrality of the article is questionable, we cannot even agree on the meaning of the subject.
What did our most recent President do about Second amendment in the midst of VA Tech shootings

""In 2004, President Bush, through the Justice Department under Ashcroft, also issued Whether the Second Amendment Secures an Individual Right, a lengthy memorandum which traced the historical development of the Second Amendment supporting its earlier conclusion. The memo stated:
The Second Amendment secures a personal right of individuals, not a collective right that may be invoked only by a State or a quasi-collective right restricted to those persons who serve in organized militia units ""

What is Obama going to do ?

Post your comments about this irrestibale urge to bear firearms and to also harm innocent