Eric, if I understand your post , you argue that constitutional rights should only be recognized where they would help to prevent the political party in power from "entrench[ing] itself and undermin[ing] political competition" -- in other words, to help correct a political process failure.
Well, that's one reason why the Constitution (the Bill of Rights, in particular) establishes certain rights, but it's certainly not the only, or the predominant, reason. (Think of the various ends served by the Bill of Attainder Clause, the Free Speech Clause, the Free Exercise Clause, the Fourth Amendment, the right to privacy, the Fifth Amendment, the Eighth Amendment, etc.)
So, let's say that Justice Kennedy were correct, and the Second Amendment was, indeed, ratified in order to protect "the right of people living in the wilderness [which apparently includes much of D.C.] to protect themselves" -- the right of "the remote settler to defend himself and his family against hostile Indian tribes and outlaws, wolves and bears and grizzlies and things like that." (Lions and tigers and bears, oh my.)
Now, I don't think this is a very plausible reading of the Second Amendment; but let's assume that it were (as the Court appears prepared to hold -- when Kennedy settles on a particular story about constitutional value or settlement, he's usually difficult to move off it, cf. Alden v. Maine ). Why wouldn't, or shouldn't, that right be cognizable? Is your argument simply that constitution writers should not create rights except to protect against political entrenchment? If so, I suppose that's one theory of what (minimalist) constitutions ought to be about -- but what does it have to do with interpreting ours, which is designed to protect against other forms of government overreaching, too?
(In your post, you suggest that a right of self-defense would "come into conflict with mynatural right to protect myself by disarming criminals," a conflictthat "can only sensibly be resolved through political compromise." But in order for there to be such a conflict between constitutional or natural rights here, the Court would have to recognize, not a right to "protect myself by disarming criminals," but instead a right to have
protect me by disarming criminals. And on this (and any other imaginable) Court, that proposition has no support at all. Cf.