There is a despairing sense of déjà-vu enveloping the fighting in Lebanon, that what we are watching is but a rerun of a long-running and wearisomely familiar grudge match. Certainly, there is a strong element of that. But it should not obscure what is so dangerously different in this extraordinarily inflammable situation.

Previous episodes have been bad enough. The worst was Israel’s full-scale invasion of Lebanon in 1982 to drive out the Palestine Liberation Organisation. That led to a two-month siege of west Beirut that killed 19,000 people (as well as the massacre of refugees at Sabra and Shatila). It destroyed not the PLO but Israel’s reputation. And, of course, it incubated Israel’s nemesis, Hizbollah.