Do we have a constitutional right to use deadly force in defense of life (or defense against rape, kidnapping, serious bodily injury, and perhaps more)? Oddly enough, the matter hasn't been settled, and has been little studied by scholars. Fordham lawprof Nicholas Johnson has a forthcoming article on the subject, but unfortunately I couldn't find a draft of it on the Web; George Mason lawprof Nelson Lund has a response. There's a smattering of other material on it, but quite little. Here's my short section on the subject; for footnotes, see here:

Lethal self-defense is so broadly accepted that courts have rarely had occasion to confront grave restrictions on it, and thus haven't squarely decided its constitutional status. Some lower court opinions have said that there is such a right, and a recent four-Justice plurality opinion -- authored by Justice Scalia, usually no friend of unenumerated constitutional rights -- suggested the same. And the Court's unenumerated rights caselaw provides a strong case for recognizing a presumptive federal constitutional right to self-defense.

The right to self-defense is important to people's lives, and firmly rooted in longstanding American tradition. Framing-era sources refer to it as a natural right. Blackstone wrote of the right to prevent "any forcible and atrocious crime," even with lethal force, as "justifiable by the law of nature"; St. George Tucker, one of the leading American commentators of the first half of the nineteenth century, described "[t]he right of self defence" as "the first law of nature."

The right has been as broadly accepted as the rights to bear and raise children and to live with one's family members, and more broadly accepted than the right to an abortion or even the right to use contraceptives. Even if due process or the Ninth Amendment is interpreted as protecting only those rights that were recognized as important common-law rights in 1791 or 1868, self-defense would qualify. The right has never been absolute, but in this respect it is like most constitutional rights, enumerated or unenumerated.

The right is also secured by forty-four state constitutions. Twenty-one of these, dating back to the 1776 Pennsylvania Bill of Rights, expressly secure the right to "defend[] life." Forty, dating from 1776 to 1998, secure a right to keep and bear arms in defense of self, which presupposes at least the traditional core of lethal self-defense.

Two court of appeals decisions have expressly rejected a constitutional right to lethal self-defense, but with little analysis, and in the course of upholding two rules that may well be constitutional even if the constitutional right is recognized: prison disciplinary rules categorically rejecting prisoner self-defense claims, and the rare state rules requiring defendants to prove self-defense by a preponderance of the evidence. Even if prisoners ought to lack a constitutional right to self-defense, this says little about the right outside prison -- prisoners are subject to far greater constraints on most of their constitutional rights than are nonprisoners. And even if defendants may be required to prove self-defense, one can have a constitutional right and yet bear the burden of proving that the conditions for its exercise are satisfied. When the Supreme Court upheld laws placing the burden of proving self-defense on the defendant, it did so without opining on whether there's a constitutional right to self-defense.

Finally, if the Court concludes that the Second Amendment secures an individual right aimed partly at self-defense, thus endorsing the view expressed by Congress and by the White House Office of Legal Counsel, though only by a minority of federal circuit judges, then some right to self-defense might be inherently protected through the Second Amendment. But, as I argue above, a right to self-defense (though potentially limitable by gun control laws) should be recognized even without reliance on the Second Amendment.