“Their project being complete, the team disbanded.”
“Stern discipline being called for, the offending student was expelled.”
In both cases, the initial dependent clause is not superfluous to the meaning of the entire sentence: it is integral. The team disbanded because the project was complete; the student was expelled because his offense called for stern discipline. This causal relationship cannot be ignored. Reading the Second Amendment as “A well-regulated militia being necessary to the security of a free state, the right to bear arms shall not be infringed,” clearly shows the same causal relationship as the example sentences; in this case, that the right to bear arms shall not be infringed because it is essential to maintaining a well-regulated militia."
http://blogs.denverpost.com/opinion/201 ... hts/33796/
The “absolute” clause construction of the Second amendment was quite common at the time, and appears in many state constitutions and framing documents. The primary purpose in these constructions is to give the conditions under which the rest of the sentence is true or valid. As a prime example of the ablative absolute, the first clause of the Second Amendment may stand grammatically free, but serves semantically to modify or clarify the meaning of the rest of the sentence. The Framers were clearly familiar with the ablative absolute and used it not as rhetorical fluff or flourish, but as a way of clarifying intent, in this case clarifying that the right to bear arms is granted in the context and within the scope of establishing a militia. Nothing more, nothing less.