For three decades, the US and Iran have fought a very public propaganda war. But in the shadow of that PR struggle, a more deadly and covert conflict has raged: one of spies, kidnappings and bombings. This week, the public and the covert became impossibly tangled with a death sentence on Monday, a rescue on Tuesday, and an assassination on Wednesday.

The developing crisis in the Persian Gulf would be little more than pulp fiction fodder if nuclear weapons and a regional war weren't on the line.

Kiss kiss, bang bang

Early on Tuesday morning, an Iranian vessel was sinking in the northern end of the Persian Gulf, its crew shooting off flares and waving flashlights in a desperate attempt to be saved as their ship flooded. To their rescue came a US Coast Guard crew. They brought six Iranian crew members aboard and gave them “water, blankets and halal meals”.

"Saving lives is the last thing you expect to do at 03.00 while patrolling in the northern Arabian Gulf, but being in the coast guard, that's what we are trained to do," said the ship's medic. But it wasn't too unusual: just the week before, the US Navy rescued twelve Iranian sailors held captive by pirates in the Sea of Oman.

The rescues don't seem to have exactly brought the countries together: the day before the second rescue, Iran announced it would put to death Iranian-American Amir Mirza Hekmati for being a CIA spy. And officials in Tehran have shown no signs of backtracking on a promise to use "full force" on US warships (including the ones doing the rescuing) returning to the Gulf through the Iranian-controlled strait of Hormuz.

On Wednesday, the action went ashore: Mostafa Ahmadi-Roshan, a 32-year-old Iranian nuclear scientist, was killed by a magnetised car bomb affixed to his Peugeot by a mysterious man on a motorcycle. Ahmadi-Roshan was the fifth Iranian with connections to the country's nuclear programme to be assassinated in the last two years. Iran promptly blamed Israel and the US.

Pre-nuclear brinksmanship

Whether Iran is developing a nuclear weapon is still unknown: a 2003 US National Intelligence Estimate said that Iran had suspended its efforts, but a November report from the IAEA suggests otherwise. What is certain is that a nuclear-armed Iran would have much more leverage across the region.

That is deeply worrying for the US and for Israel – indeed, Israeli leaders have repeatedly threatened to take out Iran's nuclear capacity. Israel's stalwart allies in the US insist they will take no options off the table. Few believe that a nuclear-armed Iran would actually launch a nuclear strike (particularly against a country like Israel, which has a massive nuclear arsenal), but it would rapidly destabilise the region's balance of power.

As unpalatable as a second nuclear power in the Middle East would be, the alternative – a pre-emptive strike on Iran – could be much worse. Iran, which has a powerful army of its own, also has potent proxies in Lebanon, Gaza and Iraq, and could mine the tanker-bearing strait of Hormuz in a matter of hours. A strike would likely lead to regional war and possibly attacks in the west. But Iran hasn't fought back yet: so far, the attacks are only over there.

Take action: Our leaders have told us that there are only two options: attack Iran or let them get the bomb. But there is a third. Let's call for disarmament globally. Nuclear weapons are an existential threat to the species, not just Israel. It's time to put an end to this dangerous game.