I WONDER whether President Biden was troubled by the readings at mass on Sunday. “It was you who condemned the innocent and killed them; they offered you no resistance,” said the Epistle of St James. “If your hand should cause you to sin, cut it off,” said St Mark’s Gospel. Did they, perhaps, prompt him to consider the ethics of his backing for Israel’s war tactics?

Two days later, Israel invaded Lebanon, contrary to President Biden’s advice. Emboldened by recent military successes, the Israeli Prime Minister, Benjamin Netanyahu, chose to ignore President Biden, much as he has done all year. President Biden has tried to tread an impossible line, offering Israel unqualified support while simultaneously trying to restrain Mr Netanyahu’s excesses. Only once has he momentarily paused the export of high-payload US munitions to Israel.

Israel has a right to defend itself. But the methods that it chooses can be alarming. The Just War principle of proportionality is useful here. The wholesale bombing of Gaza — where most of the 40,000 dead are women and children — is clearly not a proportionate way of attacking Hamas. In the past, I have argued for the greater use of Israel’s special forces in the targeting of Hamas leaders (13 October 2023). But that might have meant more Israeli army casualties. Mr Netanyahu opted for a scorched-earth policy.

And there is nothing proportionate about his policy in the Occupied West Bank, where unarmed Palestinians have been attacked by armed Israeli settlers intent on stealing yet more of their land, in violation of international law, while Israeli soldiers stand idly by. Some 700 Palestinians have been killed there by Israeli fire, out of the spotlight of the international media. One of the maps that Mr Netanyahu presented to the UN General Assembly showed Israel with no borders with Gaza and the West Bank — as if they had already been annexed.

So, how proportionate are the tactics now being used against Hezbollah? Human-rights advocates complain that inserting explosives into pagers and walkie-talkies was illegal under the international convention outlawing booby-traps. But the devices were distributed only to Hezbollah operatives; injuries to civilians were fairly minimal; so proportionality is not at issue. And the bunker-busting 2000-lb American bombs with which Israel targeted Hassan Nasrallah and other Hezbollah leaders killed only — this is the language of war — 92 civilians.

According to the Netanyahu calculus, that level of collateral damage is a price well worth paying. Yet the cost of an invasion to allow 60,000 Israelis to return to their homes in the north of Israel has been to make a million people homeless in Lebanon.

It is easy for outsiders to adopt a high moral tone here. No one is bombing our homeland (although, when the IRA did, Britain did not carpet-bomb Northern Ireland). Proportion should be the ethical lens by which we judge events as they unfold. In Lebanon, Israel should restrict itself to dismantling Hezbollah’s border-zone military infrastructure in accordance with UN resolution 1701. And President Biden must exert all the leverage at his disposal to ensure that Israel’s response to Iran’s retaliatory missile attack is calibrated to be precisely proportional.

But, ultimately, an unending policy of an eye for an eye will leave the whole of the Middle East without sight.