Once more unto the parapet, dear friends, once more.

If their questions on Tuesday were any indication (and assuredly they were), at least five of the nine justices of the U.S. Supreme Court are about to overturn an opinion the court formalized in 1939 and the nation held since its founding — that the so-called "right to bear arms" amendment to the Constitution is corporate, not individual. Not even the most venturesome Las Vegas gambler would bet against the court’s coming down on the side of every Tom, Dick, and Dirty Harry.

The only question, according to most court observers, is whether the majority will also rule that, as an individual right, it is not subject to regulations that would restrict the use of guns in any way. Tuesday’s nearly two-hour exchange between justices and advocates offered ambiguous clues, at best.

Of specific interest in the case at hand, District of Columbia v. Heller, is a Washington, D.C., regulation requiring safety lock mechanisms on guns. Opponents argue that these mechanisms make the guns more difficult to engage in a crisis, thereby defeating the purpose of any "right to bear arms."

The safety locks are there for a reason, of course. While it is true that people kill people, often they do so with guns, Sometimes the discharge is accidental. Much too often, it is a child who is the victim, at the rate of one child every one hour and 51 minutes, according to accepted statistics.

To be sure, a library’s worth of restrictions will not prevent one person from killing another, if he or she has the desire to do so. Yet if there is a way to make a gun less likely to fire accidentally, the sensible thing to do, it seems, would be to proceed.

Whether a high court majority agrees will be known in late June. If the justices were making decisions based on Jewish law, however, the outcome would be less uncertain. Putting safety locks on gins would seem to be the halachic thing to do. It is not black and white, however.

And so to the parapet. Torah law requires that, when building a house, a person must build a parapet around the roof, "that you should not bring any blood upon your house, if any man falls from there." (See Deuteronomy ”:8.)

The Talmud subjects this law to the broadest interpretation possible. Thus, we are told in the Babylonian Talmud tractate Bava Kama 15b: "Rabbi Natan says: from where do we derive [the rule] that no one should breed a bad dog in his house, or keep a damaged ladder in his house? From the text, ‘You should not bring any blood upon your house.’"

Maimonides explains that this includes "everything that is inherently dangerous and could, in normal circumstances, cause a person to die." Anything that fits that bill requires a "parapet" to be built around it, meaning that every effort must be extended to prevent the item from causing an unintentional death. (See his Mishneh Torah, The Laws of Murder and the Preservation of Life, Chapter 11:4.)

Other commentators also note, as Rabbi Samson Raphael Hirsch does, that the Torah’s "parapet" declaration even requires "local civil authorities to intervene to have anything at all which might be dangerous removed" from a person’s premises. (See his commentary on Deuteronomy ”:8.)

Weapons, of course, are made with the perfect knowledge that they can kill. A police officer or a soldier in wartime requires a gun that will perform its deadly task efficiently and with all possible speed, if the circumstances require it. It even is true, in the words of Justice Anthony Kennedy at Tuesday’s session, to "the remote settler [who needs] to defend himself and his family against hostile Indian tribes and outlaws, wolves and bears and grizzlies, and things like that."

It is not necessarily true, however, of the homeowner or storekeeper, for whom a gun is meant to provide psychological comfort and who expects the gun to deter crime, without having to employ its deadly power.

Distinction thus must be made between the offensive weapon and the defensive one. While a "parapet" is required for both, the nature of the protective device is necessarily different for each. The offensive weapon should be safe enough to reasonably protect against mishaps, but not so encumbered that it is virtually useless in the field. The defensive weapon should also be able to be used if the need arises, God forbid, but the degree of safety against mishaps must be greater.

With this in mind, it is possible to argue that guns intended for self-defense must have the best available protection against accidental or unauthorized use, or else they may not be manufactured. If they are manufactured without such devices, they may not be purchased. Yet let us assume that no one manufactures a defensive weapon that uses the best available protection against accidental or unauthorized use. If there nevertheless is a perceived or well-established need for self-defense weapons, does the requirement for a "parapet" prohibit obtaining such a weapon despite the need?

The simple answer is, "Of course not." Preservation of life takes precedence over virtually everything else, including Shabbat observance. (See especially BT Yoma 84b; note, too, the exceptions to the rule.)

The more complicated answer requires evaluating a variety of factors. Among these are whether the danger is real; whether other modes of defense would accomplish the same end; whether the degree of protection against accidental discharge is so great that it renders gun ownership moot; and so forth.

Clearly, there are many in our community who will disagree with this column. Jews own guns, too, and cherish the right to bear arms as much as Charlton Heston does. I ask them, though, to consider this: One child died of a gunshot wound while I wrote and edited this column. Another will die before the editor of this newspaper processes it and sends it to the composing room.

Do these children not have rights?

Shammai Engelmayer is rabbi of the Conservative synagogue Temple Israel Community Center in Cliffside Park and an instructor in the UJA-Federation-sponsored Florence Melton Adult Mini-School of the Hebrew University. He is the editor of Judaism: A Journal of Jewish Life and Thought.