The international “community” and its academic justifiers have claimed that Israel’s attacks on Hezbollah communications devices are unlawful. They are dead wrong.

The law of war is based on two fundamental principles: first, the distinction between the targeting of combatants and civilians; second, the requirement of proportionality in attacking targets that include both.

Under these principles, Israel’s actions were completely justified.

The law is clear that if a person becomes a combatant, he is a legitimate military target. Becoming a combatant in this case includes joining or assisting Hezbollah, harboring its terrorists or allowing one’s home or building to be used by Israel’s enemies.

The law is also clear that once someone becomes a combatant, he or she can be targeted as long as they retain that status, unless they surrender or openly declare themselves no longer affiliated with the combatant organization. This is especially so with regard to a terrorist group like Hezbollah that comprises both full-time soldiers and part-time terrorists, who may hold other jobs when not participating in military activities all the time.

If a person qualifies as a combatant, he or she may be targeted and killed while asleep, at work or at play. Combatants need not be actively involved in combat at the moment they are killed. Nor do they need to be actively committing terrorism when targeted. It is enough that they maintain the status of combatant.

The individuals who were given beepers, radios and other communication devices by Hezbollah were clearly combatants. Their deaths and injuries were lawful, even if they were shopping or walking when blown up.

But a small number of noncombatants — including children — were also killed or injured. That is where the requirement of proportionality comes in. Israel had to know that it was impossible to blow up so many devices without causing some collateral damage to innocent civilians. That is the case with regard to virtually every military action, especially those conducted in crowded urban areas such as Beirut.

The law of warfare does not prohibit such actions outright, nor should it. But it imposes restrictions based on proportionality. That rule requires that those planning a military or intelligence operation that will inevitably kill or injure some noncombatants must make reasonable efforts, consistent with military goals, to minimize civilian casualties.

They must satisfy the criteria of proportionality, which means that the anticipated civilian casualties must be proportional to the military value of the combatant targets. There is no magic formula for achieving this result. The military action must simply be reasonable under the circumstances.

In other wars, the ratios have been in the range of three or four noncombatant deaths for every combatant death. In Gaza, it has been closer to two noncombatants to one combatant. In the recent beeper and radio attacks, the number of civilian deaths and injuries were considerably lower than those of combatants.

Yet the international community and academics have criticized Israel for violating the laws of war. They are dangerously wrong, and Israel should not be deterred from similar actions based on the biases of those who misuse the law as a weapon against the embattled nation-state of the Jewish people.

Dershowitz’s latest book is “War Against the Jews: How to End Hamas Barbarism.” Stein is a former president of the New York City Council.

The views and opinions expressed in this commentary are those of the author and do not reflect the official position of the Daily Caller News Foundation.