Mercy is a good thing -- but so is justice.

And when mercy is perceived by the most vicious of one's enemies to be weakness rather than virtue, and therefore to become more vicious, then mercy becomes a vice which must be set aside in the name of a more firm devotion to bringing justice to those enemies.

Rabbi Shmuley Boteach brings the issue of the death penalty for terrorists to the fore.

IT IS time that we articulate what few wish to, namely, that Israel must finally institute a death penalty for convicted terrorists.

To be sure, human life is of infinite value and every human being is equally a child of God. No country upholds this statute more than Israel, which is why it is prepared to set killers free just to retrieve the bodies of its fallen soldiers. Israel could have defeated Hizbullah and Hamas with ease had it not always limited its overwhelming firepower to protect innocent civilians. A country this virtuous naturally balks from putting anyone, even terrorists, to death.

Indeed, since the Nazi Eichmann, there has been no execution in Israel.

And as a result, Israel has been forced to exchange some of the worst of the worst terrorist murderers for captured soldiers -- or the mutilated bodies of soldiers who had been tortured to death by terrorists of the same ilk as those released.

What to do?

As for those who argue that if Israel puts its terrorist captives to death the same will be done to its soldiers once captured, I ask, does anyone seriously believe that it would be otherwise? We once believed that Goldwasser and Regev might likewise come home alive, and for two years Hizbullah manipulated the emotions of the country to believe just that. But like so many other Israeli prisoners before them, they ultimately came home in a box.

I am not suggesting that Israel take unilateral action and simply hang captured terrorists. They should be given a fair trial, just like Kuntar, in which he was found guilty and sentenced to more than 500 years in prison. But once found guilty and allowed an appeal, if their conviction is upheld, they must be executed.

There are times when a country must temporarily violate a principle to ensure it is upheld. Police cars speed to catch those who themselves speed on highways, thereby endangering other motorists. Surgeons cut open people's chests with knives to save their blocked arteries and stopped hearts. And just governments must sometimes take the lives of unrepentant terrorist mass-murderers to protect and uphold the infinite value of human life.

Indeed, I'd argue that there is a moral imperative for the removal of such diseased specimens of humanity from this mortal coil. After all, mercy has gotten Israel precisely nothing.