Israel’s operations against Hezbollah in Lebanon and Hamas in Gaza have been widely condemned in Europe, the Arab world and at the United Nations as violations of international law. Some of the critics seem to deny that Israel has any legitimate right to use force. Others, while acknowledging its right to self-defense, nevertheless regard its exercise in these cases as illegal.
In fact, Israel’s conduct has been fully compliant with the applicable norms of international law.
The primary claim by Israel’s critics is that it used force disproportionately in response to Hezbollah’s initial attack against Israeli soldiers, eight of whom were killed and two captured. The underlying assumption appears to be that Israel should have treated these provocations as terrorist acts and limited its response accordingly, rather than as justifications for a full-scale attack on Lebanese territory.
But in determining the existence of a legitimate casus belli , a state is entitled to consider the entire context of the threat it faces. Hezbollah is not simply a terrorist gang, like Germany’s Baader-Meinhof or Italy’s Red Brigades. It is a substantial political and military organization that has more than 12,000 short- and medium-range rockets and that has operated freely on Lebanese territory for many years, periodically launching attacks against Israel. Its stated goal is Israel’s destruction, and it is the client of a major regional power — Iran — whose government appears dedicated to the same goal.
Moreover, although international law requires a state to have a lawful reason to use force — such as self-defense — it does not mandate that a state limit its military response to “tit for tat” actions. Once a country has suffered an armed attack, it is entitled to identify the source of that attack and to eliminate its adversary’s ability to attack again. Its actions must be consistent with otherwise applicable international norms, but it is not required to accept a limited conflict that fails to meet and resolve the danger it faces.
That Lebanon has suffered from Israel’s actions does not change the legal rules involved. No state has the right to permit a foreign military force to use its territory to launch attacks against another country. Indeed, every country has an obligation to control its own territory. Lebanon’s failure (or refusal) to expel Hezbollah would in and of itself have been a legitimate cause for Israeli military action. It was the Taliban’s sheltering of al-Qaeda that was the basis of the U.S. attack on Afghanistan in 2001. And, although the current Lebanese government is certainly more democratic than the feudalistic Taliban, democratic credentials cannot insulate a state from responsibility for controlling its territory.