"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."
You undoubtedly recognize the text of the 2d Amendment to the US Constitution.
Note how the meticulous authors started their sentence. With a conditional clause, which literally sets the conditions that define the rest of the sentence, that the "right" enumerated thereafter is in the context of "A well regulated Militia."
Wanna know why the "Founding Fathers" were so meticulous on this point? Ask yourself this question, would anyone define a "neighborhood watch committee" as "A well regulated Militia?"
No. "Watch committees" are to keep watch; militias are paramilitary forces. The latter need "to keep and bear arms", to protect their assigned areas and country in an effective and "regulated" manner. Watch committees and the members who serve on them do not.
Had George Zimmerman not had a gun, had he only used his eyes to report a suspected intruder, had he only ignored the advice from up his chain of command to back off, and continued to surveil his "suspect," the worst thing that could have happened would have been that, in trying to make an unauthorized and probably illegal "citizen's arrest," Zimmerman might have come to blows with the innocent Trayvon Martin who was simply walking to his parent's home. The most serious consequences: cuts and bruises and, probably, Zimmerman's forced retirement as a "neighborhood watcher."
Given Florida law, especially the repulsive "Stand Your Ground" statute which says, "If I say you scared me, I can kill you with impunity," a conviction in this case was never likely. Whatever went down in Sanford, Florida, will never been known "beyond a reasonable doubt."
What can be judged from "the preponderance of the evidence" we will undoubtedly learn in a civil trial. Chances are that the civil jury will decide that George Zimmerman used bad judgment in stalking a fellow citizen based on a resentment that "they've been getting away with" whatever it was he suspected Trayvon Martin wanted to do beyond return to his Dad's domicile, and worse judgment in ignoring the real police officer's advice to back off. His worst misjudgment, the one that produced the wholly unneccessary, wholly avoidable tragedy, was pulling a gun and using it.
In that last act, he had criminal accessories before the fact, Chief Justice John Roberts, and Justices Antonin Scalia, Anthony Kennedy, Clarence Thomas and Samuel Alito, a quintet also guilty of willful abuse of the US Constitution they were sworn to defend and intepret.
They blew off close to 200 years of judicial precedent to create the worst "entitlement" in America's history, the "right" of any asshole to possess deadly force.
As much as anyone, even poor George Zimmerman, their hands are soaked in Trayvon Martin's innocent blood.