The war drums have been beating – again – in Israel. The latest alarm was started by two usually well-briefed journalists, Nahum Barnea and Shimon Shiffer, who wrote that an Israeli attack on Iran's nuclear facilities could come in weeks, rather than months, and before the US presidential election in November. Their story contained a caveat: if the decision to attack were up to Binyamin Netanyahu and Ehud Barak alone. Because plainly, it is not.

The enthusiasm of Israel's prime minister and defence minister for an air strike on Iran appears to have united their country's defence and security establishment against them, including Israel's new minister for homeland security. The two have yet even to convince their own inner cabinet. But the report was taken so seriously that Barnea amended it on Monday by speculating that Barak, the thinly disguised source, may be trying to cover his own back, in the knowledge that such an attack will never be launched. Barak's reasoning depends only partially on Iran's alleged actions, and the latest US intelligence assessment that Tehran now possesses 170 kilograms of medium-enriched uranium, from which it is relatively easy to produce bomb-grade material. Barak is worried that so many centrifuges are being hidden underground that they will soon be out of Israel's military reach. After that point, Israel will have to rely on a US president it suspects will never order an attack .

Barak's case for an airstrike now is peppered with inconsistencies – not least the calculation that if Israel attacked, Iran would be rational enough not to retaliate against US military targets in the Gulf and hence the regional war everyone feared would not materialise. This confidence is not shared by his military chiefs. But to take Barak's war-gaming at face value, if Iran were rational enough to contain its response, it would prove that deterrence works for a state Netanyahu continues to describe as an irrational actor motivated by messianism. If Barak is right, the deterrence of mutually assured destruction would work all the more if Iran acquired a bomb, particularly as Israel has several hundred of them.

Loud talk of an impending airstrike could be no more than an attempt to twist Washington's arm. If it is, nothing should stiffen Barack Obama's resolve to prevent it happening more than the thought that Netanyahu is not just playing politics in his own country but in America too. Netanyahu foolishly dares Obama not to cast his veto, because if he did, Mitt Romney his Republican challenger would make hay with the idea that the Democat in the White House endangers Israel's security. This lever will no longer work after the election, hence the November deadline. Even as bluff it is dangerous, and eminently combustible in a tinder-dry Middle East.