We spectators of the shadowy war between terrorist organizations and governmental intelligence agencies do not yet know exactly who killed Hezbollah military chief Imad Mughniyeh in the Syrian capital of Damascus last week. It could have been just about anyone, starting with the Syrians themselves.

Improbable? Perhaps. But how can we be sure that Mughniyeh was not romancing some Syrian general’s wife, or muscling in on some Syrian politician’s drug turf, and that this was not the reason a bomb found its way into his car?

When you’re Imad Mughniyeh, who killed many people, there are lots of people who would like to kill you.

Let’s assume, though, that Israel was indeed behind the Mughniyeh assassination, acting either alone or in concert with others. And let’s assume that, given Mughniyeh’s long history of terrorist operations, it was in Israel’s justified interest to kill him.

Let’s assume, too, that, knowing Israel was responsible, Hezbollah now intends to strike back, not directly at Israel itself, which could trigger yet another Israeli assault on Hezbollah positions in Lebanon, but — as Hezbollah leader Hassan Nasrallah has implicitly threatened — at targets outside of Israel.

And let’s assume again that these targets may be not just Israeli, but local Jewish ones as well, as happened with the Jewish community headquarters in Buenos Aires, blown up in 1994, in a joint Hezbollah-Iranian operation, with the death of 85 people.

The question, then, is: Does Israel have the right to jeopardize Jewish lives in the Diaspora on behalf of its own interests? Is it wise for it to do so?

In one sense, of course, the very existence of Israel may jeopardize Jewish lives elsewhere. Terror attacks on Jewish community centers, synagogues, schools, restaurants, and so on all over the world have been part of the Palestinian war against Israel for decades, and have rarely been occasioned by specific Israeli actions. Moreover, the Israeli-Arab conflict has led to a worldwide increase in anti-Semitism, which itself puts Jews at risk. One can hardly expect Israel to agree to disappear in order to reduce the risk level to zero. Nor can one expect it to make major strategic decisions on the basis of how the Diaspora’s Jews might be affected by them.

On the other hand, the Mughniyeh assassination was not strategic. It involved a tactical decision, and the blow it struck against Islamic and anti-Israel terror, however effective, was limited. Mughniyeh will have his replacement, and the damage caused to Hezbollah will be repaired within a few weeks or months. Although Israel has no reason to mourn his death, it also could have refrained from killing him at no great harm to itself. Should it have done so out of concern for Diaspora Jews?

On a purely pragmatic level, the answer might be yes. Perhaps the number of lives saved by ridding the world of Imad Mughniyeh will not equal the number of lives lost to the revenge that Hezbollah will take. But in that case, Israel should have resisted the temptation to kill Mughniyeh out of concern for its own citizens, too. Hezbollah, after all, also will be looking — perhaps primarily — for Israeli targets throughout the world. All Israelis going abroad have been warned of this: Israeli institutions everywhere have been put on a state of alert. If in the end a heavy price is paid by someone, Israeli, Diaspora Jew, or anyone else, it may indeed not have been worth it.

But these are the imponderables of any war. The decision makers make their calculations and take their chances. Sometimes they are right, sometimes they are wrong, and sometimes one never knows. Not only can no one predict what the precise effects of killing an Imad Mughniyeh will be, it may be impossible to sum up years later what the precise effects were. The variables are simply too many, the interrelations between events too complex.

As a matter of principle, though, I do not think Israel need be more concerned about possible terrorist retaliation against Jews or Jewish communities in other countries than it need be about possible retaliation against Israelis. For better or for worse, the Jews of the world have been part of the Israeli-Palestinian and Israeli-Arab conflict since its inception. Some of them have been proud of this and some indignant, but none has been unaffected. This is inherent in Israel’s situation as the home of a people that also lives outside of it.

Yet in point of fact, the Jews of the world who might be endangered by the Mughniyeh killing are almost entirely those who identify with Israel and care about it. These are the Jews who attend the synagogues and community centers, and send their children to the Jewish schools, that Hezbollah would be most likely to attack.

For years now, many of these institutions have been obliged to take protective measures against such a possibility. I am not aware of the Jews served by them complaining about this or blaming Israel for it. It is among the Jews who keep away from Jewish life and are not in danger when Jewish institutions are targeted that one finds Israel blamed the most.

By any standard, Israelis bear nearly all the brunt of Israel’s wars. This is how it should be. But it is not unreasonable that Jews elsewhere to whom Israel is important should also sometimes be asked to run a small risk. Imad Mughniyeh, after all, was their enemy too.

Mr. Halkin is a contributing editor of The New York Sun.