Tensions between Iran and the US seem to be going up a notch every day. After Iran announced that it had begun enriching uranium inside a mountain north of Qom, Tehran has now sentenced to death a former US marine on a charge of spying.
In between the two provocations, US Defense Secretary Leon Panetta threatened a "response" if Iran crossed a "red line" by blocking the crucial trade route through the Strait of Hormuz.
This in itself was Iran's response to the European Union's proposed new round of oil sanctions - which were the EU's response to Iran's refusal to stop its uranium enrichment plan. The wheel keeps turning.
Such tit-for-tat threats - followed by partial diplomatic retreats - have been de rigueur for relations between Iran and the West for many years. But the increased pace of measures and countermeasures in recent weeks seems to have made the prospect of a military conflict loom larger than ever.
"In the last two weeks, we haven't just seen a rhetorical escalation, but also a military one, with Iran's naval excercises. So it is a serious situation," points out Konstantin Kosten of German political research institute the Friedrich Ebert Foundation (FES).
Both the US and Israel have refused to rule out an airstrike against Iran's nuclear program, and serious diplomatic spats - such as November's attack on the British embassy in Tehran - seem to be happening more frequently.
On top of this, Israel announced Saturday that it was boosting its defense budget by six percent - or three billion shekels ($780 million) - this year.
For Alexandr Burilkov, Iran expert at the German Institute of Global and Area Studies (GIGA), this is where an airstrike is most likely to come from.
"With Israel, I think the possibility of war is greater," he told Deutsche Welle. "The current political climate in Israel makes military action in the spring more likely."
"That would have huge regional implications," he added. "Anything that Iran does in the Persian Gulf in retaliation doesn't just threaten the US and European oil interests, but also Saudi Arabia, the United Arab Emirates and even China."
But despite all the saber-rattling, Kosten thinks an airstrike remains unlikely at this stage. "I wouldn't say that that means there will be an attack," he said. "Both sides - the US and Iran - have absolutely no interest in an escalation."
The uncertainty of war
The underlying problem is that any kind of military conflict - even a single airstrike on Iran's nuclear program by Israel, or an attempt to block the Strait of Hormuz by Iran - involves far too many uncertainties and negative consequences.
"I think closing the straits is actually militarily impossible for Iran," says Burilkov. "But also it would be a last-ditch measure, as it would be devastating to the economy."
As for the airstrike option, while Burilkov does not believe Iran's claim that its underground bunkers are inpenetrable, he also thinks that results are far from certain.
"These bunkers are not immune to airstrikes anymore," he said. "Israel has acquired bunker busters from the US in the past few years. But the bunkers are so deep that the results are not guaranteed, which might deter the Israelis."
More than this, he thinks even a successful airstrike is only a temporary solution. "The problem is that if Israel does decide to bomb the nuclear installations, the infrastructure is solid enough that they would be able to get themselves up and running again within three years at the most," he predicts. "It's not like when they bombed Iraq in the early 80s - they bombed them once and the program was basically completely ended."
Uncertainty over Iran's objectives
The central question, which the international community has been wrestling with for at least a decade, is clear: is Iran building nuclear weapons or not?
Kosten is very circumspect on the issue. "No one has a clear yes or no," he said. "There are many, many reasons to be suspicious, and there have been for many years, of Iran's claim that it is only interested in a civilian program. But at the same time, there are indications of a discussion within Iran about whether they really want to do it. There are people there who see the path to a nuclear weapon as the path to political isolation."
Burilkov has no such doubts. "I think it's clear that they are building a weapon," he said. "The IAEA report shows the Iranian program has all the hallmarks of a weapon designed to be put inside a missile warhead. I'd say it will take them about two years."
Despite Iran's aggressive intentions and the dangerous brinkmanship, war clearly remains a reluctant option for both sides. President Barack Obama has very little to gain from a strike before the election in November, even though he has faced fierce attacks from Republican presidential candidates over his Iran policy.
But at the same time it also seems certain that the next diplomatic crisis is just around the corner, when the EU meets at the end of this month.
"The big question is how will Iran react to an EU oil embargo, which will very probably be delcared at the end of January," said Kosten. "Will they really block the Strait of Hormuz, or not? That is very unclear. There are factions in Iran who certainly have a vested interest in an escalation, but there are also factions that think it will lead to problems."
Then the game of tit-for-tat can begin again.
Author: Ben Knight
Editor: Rob Mudge