Regime will do whatever it takes to cling on to power – including sacrificing economies of other Gulf states

Brinkmanship, the ability to take a country to the edge of war without plunging it into the abyss, was the cornerstone of cold war diplomacy. But in our different, more unstable times – in which the line between state and non-state actors has blurred, and weapons of war have diffused – the world this week finally tipped over the edge, and suddenly it is in freefall.

The first six days of the Iran war cost the US $12.7bn (£9.5bn), but now the Pentagon is seeking as much as $200bn in military funding. Oil at $125 a barrel is no longer an Iranian, or Russian, fantasy. The crown jewel of Qatar, Ras Laffan – the world’s largest liquefied natural gas plant – may not reopen fully for five years, at a cost of $20bn a year. Other combustible oil depots in the Gulf, from Bahrain to Abu Dhabi, are exposed to Iran’s low-cost drones. Then add the human cost of 18,000 civilians injured and more than 3,000 killed in Iran alone.

The regime in Tehran, fighting for its survival, had long warned that if it were attacked it would retaliate by targeting American bases in the region. Yet Donald Trump, the US president, seemed surprised when it did so. Inured to decades of isolation and condemnation, Ali Khamenei, the late supreme leader, said at the beginning of February: “The Americans should know that if they start a war, this time it will be a regional war.”