Israel-Iran: attack imminent?
Yes, I know, the question has been asked repeatedly over the past few years -- but I'm afraid it's time to ask it again.
As my colleague Mark Mardell, the BBC's North America editor, put it in a blogpost a couple of days ago: "The drumbeat of war has grown louder in the past few days."
That drumbeat emanates from Israel, where the defence minister, Ehud Barak, talks of Iran soon entering a "zone of immunity", in other words a moment when its uranium enrichment programme will be so well protected in deep underground bunkers that it will become virtually impregnable.
According to the Washington Post, the US defence secretary Leon Panetta "believes there is a strong likelihood that Israel will strike Iran in April, May or June ... Very soon, the Israelis fear, the Iranians will have stored enough enriched uranium in deep underground facilities to make a weapon -- and only the United States could then stop them militarily."
And the New York Times reported this week: "Amid mounting tensions over whether Israel will carry out a military strike against Iran's nuclear program, the United States and Israel remain at odds over a fundamental question: whether Iran's crucial nuclear facilities are about to become impregnable."
Yes, says Mr Barak; No, say the Americans. The Washington view is that the ever tighter sanctions imposed on Iran are having a real effect, so the best policy is to let them bite harder. The Israelis say they can't risk waiting much longer.
For several decades now, a vital element in Israel's security strategy has been its status as the only nuclear power in the Middle East. (It has never admitted as much, but it's perfectly happy for everyone else to say so.)
But if Iran were to become the region's second nuclear-capable power, that invaluable strategic superiority would be wiped out at a stroke. Israel would, in theory, then itself be vulnerable to a nuclear attack.
Iran, of course, sees things exactly the other way round. It has had nuclear ambitions since the days of the Shah, and no Iranian politician, not even the reformists like Mir-Hussein Moussavi, is prepared to give up Iran's right to develop a nuclear programme, officially solely for peaceful use.
Iranians remember a glorious past when the Persian empire stretched right across the region and included what is now Israel. (Just a few days ago, the deputy Israeli prime minister Silvan Shalom said he believes Iran is now trying to revive that former empire.)
But imagine you were an Iranian strategic planner. You have recently gained valuable extra regional influence with the US-engineered overthrow of your old enemy Saddam Hussein in neighbouring Iraq, and the installation in Baghdad of a much more friendly, Shia-dominated government.
But to your west, the signs are a lot less encouraging. Your long-time allies in Syria are in deep trouble, and if they are defeated, their place will be taken by a Sunni-dominated administation with no great love for Tehran.
Coming after a string of Arab upheavals that have vastly increased the influence of the Sunni Muslim Brotherhood across the region (aided and abetted by the unimaginably wealthy Qataris), the overthrow of the Assad dynasty in Damascus would be extremely bad news.
So, as you analyse the rapidly shifting power relationships, would you be in the mood to give up a nuclear programme that earns you the attention -- and yes, the fear too -- of your neighbours?
Iran's leaders are not, as the Americans would say, in a good place. The man in charge, the supreme leader Ayatollah Ali Khamenei, is elderly and said to be in poor health. He has fallen out with the president, Mahmoud Ahmadinejad, who is now said to wield little real power.
The economy is in a mess, and many poorer Iranians are finding it increasingly difficult to make ends meet. Uncertainty beyond the country's borders is matched by growing restiveness at home.
According to the Washington Post: "US officials don't think that [Israeli prime minister] Netanyahu has made a final decision to attack, and they note that top Israeli intelligence officials remain sceptical of the project. But senior Americans doubt that the Israelis are bluffing. They're worrying about the guns of spring -- and the unintended consequences."