The Caroline case established that there had to exist "a necessity of self-defence, and that any action taken must be proportional", since the act justified by the necessity of self-defence must be limited by that necessity, and kept within it.
On the surface, Israel's current response to Hamas rocket attacks would seem clearly disproportionate to the danger.
However, airstrikes combined with a possible ground incursion is still a relatively restrained response when measured against the full capabilities of the IDF.
Israel is after all one of the most advanced fighting forces in the world. A disproportionate response, and within IDF capabilities, would be to flatten Gaza completely.
Critics of Israeli military actions against Hamas have never clearly articulated what they would consider to be a proportionate response to nearly a decade of indiscriminate rocket attacks on civilians.
And Hamas is hardly blameless in this conflict. Israel and Hamas have long believed in, and prepared for, the fight that was considered to be inevitable by both sides.
The dilemma for Israel is not the proportionality of its response. The difficult task ahead will be turning battlefield victories into a political triumph. War is after all, an instrument of politics.
Killing Hamas leaders and downgrading their rocket attack capabilities will certainly yield short-term security gains for Israel.
But a clear victor is unlikely to emerge from the fog of this war. What is evident is that a public relations disaster will come at great political and strategic cost to Israel. Antagonizing the moderate Arab states, and empowering grass-roots support for Hamas, may ultimately turn battlefield success into strategic failure for Israel.
And the clock is ticking against Israel.
Hiding amongst the civilian population, Hamas is everywhere and nowhere; benefiting from every incidence of collateral damage.
Each civilian casualty erodes Israel's moral high ground in justifying its military operations as self-defence.
The danger for Israel is that it needs to turn this war into a meaningful peace in order to declare victory. All Hamas needs to do is survive to fight another day.
Aaron Lim completed his master's thesis on military strategy. He has worked as an analyst for the New Zealand Army and as Online Manager, New Zealand Trade and Enterprise. He has also worked as a journalist and for stock-market operator NZX.
