The Supreme court ruled in favor of Mr.Heller in which the second amendment does protect an individual's right to bear arms unconnected with service in a militia.
Decision: In a 5-4 ruling the Supreme court ruled that the second amendment does protect people's right to bear arm in defense of hearth and home. The reason behind this is because a well maintain and trained militia is meant to defend and protect people. That means people have the right to arm themselves for self-defense.
Significance: The Second Amendment protects an individual's right to posses a firearm unconnected with service in a militia, and to use the firearm for lawful purposes.