Israel may have taken a step back but for how long?

The Guardian -- When Israel's defence minister, Ehud Barak, said this week that his country was "very far off" from taking a decision about whether to bomb Iran's nuclear facilities, General Martin Dempsey, the chairman of the US joint chiefs of staff, may have allowed himself a moment of relief before boarding his flight to Tel Aviv on Thursday.

But, mindful of Israel's record of blowing hot and, well, less hot on the issue, Dempsey will still deliver a strong message to Barak, the president, Shimon Peres, the prime minister, Binyamin Netanyahu, and his Israeli military counterpart, Benny Gantz: a military strike on Iran would have dire consequences; sanctions need more time; Israel and the US must work in partnership.

Events over the past fortnight have increased US anxieties that – despite Barak's words, aimed at cooling the febrile atmosphere – Israel is actively considering steps which could plunge the region (and beyond) into a catastrophic war. Hence Barack Obama spoke directly to Netanyahu on the subject last week, the US defence secretary, Leon Panetta, privately sought assurances over Israel's intentions, and Dempsey flew in for a series of face-to-face meetings.

Iran's claim on 8 January that it planned to start nuclear enrichment at its underground Fordow plant, near Qom, "in the near future" was seen as coming perilously close to one of Israel's "red lines". It was followed a few days later by the assassination of an Iranian nuclear scientist, an operation widely attributed to the Mossad, Israel's fabled intelligence agency. Israel has maintained its usual omertà on the hit, with only Peres saying that "to the best of my knowledge" the country was not involved. Meanwhile, Iran's threat to close the Strait of Hormuz has exacerbated tensions.

This latest round of escalation comes only two months after intense speculation that Israel was gearing up for an imminent strike, with reports that Netanyahu was striving to persuade his divided cabinet to back such action. Some suggested that public sabre rattling was an attempt to persuade the international community to impose stiffer sanctions on Iran.

And, indeed, Netanyahu gave an interview last weekend in which he suggested sanctions were working. "For the first time, I see Iran wobble," he told the Australian. Three days later, he said the opposite: sanctions were ineffective, he told an Israeli parliamentary committee. US officials are uncertain how to read Israel's intentions given such contradictory statements.

But there does appear to be a real debate within Israel's political and defence establishment over the merits of military action, and one that does not necessarily run along left-right, dove-hawk lines.

The consequences of a strike are the dominant consideration. Tehran would be expected to order Hezbollah to launch a barrage of rockets from Lebanon in response. Hamas in Gaza may be instructed to do likewise, although since its relations with Tehran have cooled, there is less certainty it would comply. Even without a direct military response from Iran, Israel could find itself engaged in serious conflict on two of its borders with organisations which have significantly rearmed in the past couple of years.

Another reason for debate concerns timing. The Obama administration is unwilling to get embroiled in a military conflict in an election year. Some believe that November's poll could produce a US president more sympathetic to Israel's inclination to strike. Others say it will be too late by next year, and in any case Obama may still be in the White House.

There is another possible reason why Israel may decide not to strike, or at least not yet. Some suggest that covert operations, such as assassinations, are not just intended to impede Iran's nuclear progress but also to goad Tehran into action of its own or on its behalf by its proxies providing Israel – and the US – with a casus belli.

In his brief visit, Dempsey will attempt to identify Israel's true intentions as well as delivering a strong message. Meanwhile, the US is stepping up practical contingency plans against the possibility of war, according to the Wall Street Journal. And, in the interview in which Barak said a decision was "very far off", he also said that Washington and Israel "respect one another's freedom of decision". The implications of that will not be reassuring to American ears.