This is important, because it splits the amendment into two clauses, an independent clause and a dependent clause. (The original version is grammatically incorrect, not having an independent clause.) Note that the independent clause is “the right of the people to keep and bear arms shall not be infringed.” This expression is able to stand alone, making its meaning (with no need for a reference to a militia or any other purpose) pellucidly clear. This construction is actually very ingenious, because the sentence structure reflects real-life – the existence of a militia and the security of a free state both depend on “the right of the people to keep and bear arms.”