Since its establishment the modern State of Israel has been involved in one war after another. On matters of war (and peace), every constituency in the country weighs in with its political, social, economic and religious opinion. This is as it should be, for there is no greater life-and-death decision that a nation can make than the one to wage war. As a rabbi, I turn to our religious tradition to find guidance. Within that tradition I find an abundance of Jewish literature that discusses virtually every aspect of war. The middle chapters of Deuteronomy deal with the necessity of war, as well as with determining who must participate in battle and who is exempt; and, most critically, the manner in which war is waged. The Talmud derives from these chapters its discussion of two types of war: milhemet mitzva (obligatory) and milhemet reshut (optional). According to Jewish sources, Joshua's conquest of the Land of Israel was an obligatory war, while David's expansion of the borders of ancient Israel was optional. However, there is an intense debate in the Gemara regarding whether it is legitimate to go to war against a country to remove a possible attack in the future, and whether doing so would be obligatory or not. This controversy over what is essentially a preemptive strike is profoundly relevant to Israel's present reality; not only in how it combats terrorist assaults and tries to avert future ones, but also, and mainly, how it deals with the ominous threats emanating from Iran. In the Shulhan Aruch's commentary on the verse "When you build a new house, you shall make a parapet for your roof, so that you do not bring a bloodguilt on your house if anyone should fall from it" (Deut. 22:8), we read: "...and not only roofs must be protected against danger to human life, but any place where there exists a possibility of danger to human life requires protection. It is likewise our duty to remove any cause that might prove dangerous to human life, as we must take care of it [ourselves]), as it is written, 'But, take utmost care and watch yourself scrupulously...' (Deut. 4:9)." AND YET the talmudic text suggesting that to save a life a Jew is permitted to slay an assailant who seeks to kill him is substantially qualified. This text, widely quoted today by some religious circles in Israel to justify a harsh response to the Palestinian uprising, has been subjected to great scrutiny. In his Law of the Kings, Moses Maimonides makes it plain that killing another in self-defense is an action that is justified only when the threat to one's own life is imminent. A similarly cautionary note is sounded in the most definitive argument for a preemptive strike in what is called the "law of the pursuer." The restrictions imposed on preempting an intruder who has seemingly evil intent are so rigid that if one cannot be sure, in Maimonides's words, that the threat of death is immediate, then one must be willing to forfeit his own life before killing someone else because: "Who says your blood is redder than his blood?" The Korban Ha'eda holds that war may be undertaken "against neighbors in the fear that with the passage of time they will wage war..." This would seem to indicate that preemption falls under the category of a obligatory war, but, the Korban Ha'eda cautions that preemption can only occur if there is evidence of direct bellicose activity, otherwise preemption is considered an optional act. The notion of a preemptive war is not mentioned in Maimonides's description of obligatory war, which for Maimonides is a war against the seven nations, "lest they lead you into doing all the abhorrent things they have done for their gods..." (Deut. 20:18), a war against Amalek and a war to deliver Israel from an enemy who has attacked them. Further, Maimonides claims that one does not wage war until first seeking peace: "When you approach a city to wage war, you must first call out for peace" (Deut. 20:10). This applies to both obligatory and optional conflicts. Even if one were to argue the halachic merits of a preemptive strike because of the real threat to one's physical survival, the Talmud forewarned that we are not required to wage a war whose chances for success are limited. THE ONLY reasonable conclusion to draw after surveying Jewish texts on the notion of preemption is that extreme caution is advised, which means a preemptive strike against Iran may have to be argued not on theological grounds, but rather on historical understandings. History tells us that in 1933, when Hitler assumed the chancellorship of Germany, Mein Kampf was in its 25th printing. This manifesto that detailed the "Final Solution" should have been enough of a warning to justify a preemptive strike against Germany in order to prevent the Germans from achieving the military capability to implement Hitler's evil plan. Iran's Mahmoud Ahmadinejad is the Hitler of 2006. However, in response to his constant threats upon the life of the Jewish state, we must integrate the cautionary tone of our tradition with the painful echo of our history. Though history teaches us that a preemptive strike upon Iran may ultimately be justified, tradition instructs us to be certain that the threat to our life is immediate, and even if so, to first both seek peace and weigh the outcome of going to war - considerations born out of great wisdom.