Israel has all but declared war in the Middle East – a conflict it cannot hope to win | Simon Tisdall

The killing of Hamas's political leader has raised tensions yet again. Only a ceasefire in Gaza offers any prospect of peace

Failure to halt the war in Gaza lies at the heart of the latest lethal savagery in the Middle East. The assassination in Tehran of Hamas's political leader, Ismail Haniyeh, will be celebrated in Israel as just revenge for the 7 October atrocities. But Islamist hardliners in Iran and militant groups across the Arab world will see it as further proof of their belief that the state of Israel is a menace that must be destroyed at all costs.

And so the hatred, the violence and the misery will continue unchecked, and will in all probability worsen and spread. Just because this homicidal cycle is familiar does not mean it cannot accelerate. Few parts of the Middle East - Lebanon, Syria, Iraq, Yemen, Egypt, Jordan - have escaped the toxic fallout of the Gaza conflict. In Washington and Britain, domestic politics are roiled by the fury and the grief. The UN's impotence is daily, humiliatingly exposed. No one is immune to this poison.