Israel’s January 31 aerial attack on a Syrian research facility and arms complex has raised once again the thorny question of when preemption against a developing threat may be justified under international law—as opposed to simply strategic calculation. Predictably, the Israeli bombardment elicited a hail of criticism from some regional and global players. Syria has threatened to retaliate, while Iran has suggested that Israel would regret its violation of Syrian sovereignty. The Russian response, however, was particularly intriguing, since it highlights an ongoing disagreement over the circumstances in which the use of force may be warranted.

In the aftermath of the Israeli strike, Russia’s foreign ministry stated, “if this information is confirmed, then we are dealing with unprovoked attacks on targets on the territory of a sovereign country, which blatantly violates the UN Charter and is unacceptable, no matter the motives to justify it.”

Russia, of course, has a long history of defending the principle national sovereignty, particularly as a permanent member of the United Nations Security Council. In their complaint, Russian officials invoked paragraph four of Article 2 of the UN Charter, which reads, “all Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state….” In Moscow’s view, this uncompromising statement renders the Israeli attack on Syria unacceptable under international law.

In fact, international law contains greater ambiguities than Moscow admits. Article 2 must be read in conjunction with Article 51of the UN Charter, which reads, “nothing in the present Charter shall impair the inherent right of individual or collective self-defense if an armed attack occurs against a Member of the United Nations.” From a legal standpoint, the question is, was the Israeli attack a legitimate response to a perceived threat?

[rebelmouse-image 27086248 alt="""" original_size="499x333" expand=1]

Barak last month in Davos (World Economic Forum)

Judgement about the legality of armed force in instances of self-defense typically have to pass what is often referred to as “the Caroline test” of imminence. In 1837, British forces attacked a U.S.-flagged steamboat (the SS Caroline) being used to supply rebels in Upper Canada against the British colonial government. In his famous analysis of the incident, the U.S. Secretary of State Daniel Webster exculpated the British. “Even supposing the necessity of the moment authorized them to enter the territories of the United States at all, they did nothing unreasonable or excessive.” The act was justified, inasmuch as the “necessity of self-defense was instant, overwhelming, leaving no choice of means, and no moment of deliberation.” Subsequent international legal development has generally embraced this idea insofar as self-defense is allowed in anticipation of attacks that are imminent, though the precise contours of this standard remain contested.

Much more problematic is the launching of a “preemptive” attack against a threat that is developing but not yet imminent. A decade ago, in its 2002 National Security Strategy of the United StatesPDF, the administration of George W.Bush enunciated a right to “preemption”. The basis of this controversial doctrine was that in an age of catastrophic threats, the United States needed the leeway to launch armed attacks to protect itself from catastrophic threats that were emerging but not yet fully realized.

Israel has not acknowledged the strike, so it has not provided any legal justification, but its actions fall on the preemption side of the line. Experts speculate that it had three purposes. The first was to destroy Syrian heavy weapons, including SA-17 surface-to-air missiles, that Israel worries could be transferred to Lebanon, helping Hezbollah upgrade its offensive capabiltiies. The second was to warn Damascus not to use (or lose control of) its biological and chemical weapons, which had been the subject of research at the facility. The third was to signal to Iran Israel’s readiness to launch devastating attacks if the Iranians approach nuclear weapons capability.

As outgoing Defense Minister Ehud Barak said cryptically in Davos, the attacks provided “another proof that when we say something we mean it.”

From Israel’s perspective, the failure of the UN Security Council to act to stop the bloodshed in Syria—and prevent the spillover of weapons to its neighbors, mitigates the violation of Syrian sovereignty. The action should also be placed in the context of past missions targeting suspected nuclear facilities in Osiraq, Iraq, and Deir ez-Zor, Syria.

[rebelmouse-image 27086249 alt="""" original_size="320x209" expand=1]

(IDF)

Clearly, Israel holds a broad view of what constitutes its self-defense. This view is sustained by the fact that Israel and Syria have failed to sign a peace agreement following their most recent conflagration in 1982. For their part, Israel and Hezbollah have remained at odds following conflict in 2006 while Israel, along with the United States, has labeled them a terrorist organization. These geopolitical concerns explain the circumspect reaction from Washington. As Secretary of Defense Leon Panetta explained drily, “the United States supports whatever steps are taken to make sure these weapons don’t fall into the hands of terrorists.”

Israel’s use of force may be a prudent act of statecraft. Whether it is formally legal is another matter, and doubtless of secondary concern in Jerusalem.