The temperature between the West and Iran has increased dramatically. Escalation by both sides coupled with a reckless discourse that has normalised the idea of war have created an environment where military confrontation is a rising probability. The next escalatory step pondered by Europe - in the midst of its own economic crisis - is a total embargo on Iranian oil. An idea that a few months ago was considered a non-starter now has an air of inevitability.

Sanctions are rarely effective. But right before their imposition - at the moment where they remain a withdrawable threat - their effectiveness is at their height. The challenge with multilateral sanctions, however, is that the diplomatic resources required to create concensus around sanctions are so great that once the sanctions threat gains momentum, the commitment of the sanctioning countries to this path tends to become irreversible. Rather than utilising the threat of sanctions to compel a change in policy, they tend to confuse the means with the goal. Backing down from the threat becomes too costly so sanctions become unstoppable - and ineffective.

This is what happened in May 2010 when the Obama administration and the EU opted for a new round of UN Security Council sanctions on Iran even though Tehran at the last moment succumbed to Western demands on a fuel swap offer.

The Obama administration's limited diplomacy with Iran in October 2009 was centered on a fuel swap aimed at getting 1,200kg of Low Enriched Uranium (LEU) out of Iran in return for fuel pads for a medical research reactor and by that create greater political space for continued talks. But political infighting in Iran and Iranian demands for mechanisms that would guarantee that the fuel would be delivered caused the diplomacy to fall short.

Though the West recognised that the deal had fallen victim to internal politics in Iran, the US and the EU abandoned diplomacy and returned to the sanctions track by November 2009. But resistance from Russia and China was stiff and a new resolution could not be adopted early Spring 2010 as they had hoped. Far greater diplomatic resources and time had to be invested to win China and Russia's buy-in.

Moscow and Beijing were not the only obstacles. Turkey and Brazil, who also served on the UN Security Council at the time, believed that diplomacy could still be resurrected. With Washington's half-hearted blessing, the two states embarked on their own mediation effort in order to get Iran to yes.

With a letter in hand from Obama declaring Washington's desire to see 1,200kg of Iranian Low Enriched Uranium put in escrow in Turkey, the Brazilians and Turks headed to Tehran for an 18-hour marathon negotiation. The West did not expect them to be successful, after all, the Iranians were not interested in a deal, White House officials believed. Still, Turkey and Brazil needed to experience failure on their own in order for them to come onboard with sanctions.

After two days of talks, Brazil and Turkey shocked the West - they had an agreement. These two up and coming states had succeeded where the US and the EU powers had failed for years. Though some facts had changed on the ground, the deal - the Tehran Declaration - followed the benchmarks of the US proposal from only six months earlier and the guidelines listed in Obama's letter to the leaders of Turkey and Brazil.

But rather than viewing this as the diplomatic breakthrough the West had sought in October 2009, it was viewed as a deceptive Iranian trick. Unbeknownst to Turkey and Brazil, Obama had secured Russia and China's approval for sanctions only a day before the talks in Tehran began. Almost without reflection, Sectary of State Hillary Clinton gave the agreement the death knell, declaring in the US Senate that Washington's response was to adopt a sanctions resolution at the UN, while adding that this diplomatic efforts had made “the world more dangerous.”

The British viewed the agreement as a “distraction.” Israel's Deputy Foreign Minister Danny Ayalon told me that it was a “blatant ploy” by Iran and that Turkey and Brazil had been taken for a ride. Connecting the agreement with the UN vote in a negative way, a senior EU official told me that “If you look at the timing of the Tehran Declaration, it was done at the eve of the vote. Is that a very credible sign? ... The P5 didn't want any monkey business at that time.”

The sanctions momentum had become too great - the lure of the sanctions trumped the diplomatic breakthrough it ostensibly was supposed to bring about. Once concencus on sanctions among the five permanent members of the UN Security Council had been reached, it was deemed more valuable than a nuclear opening.

Now the EU is about to repeat this mistake. One the one hand, the EU is aggressively moving forward with an oil embargo - a step that a senior EU official explained to me as the last step short of war. On the other hand, a new round of talks is in the making.

Sceptics will argue that the Iranians are only coming to the table due to the sanctions pressure and that their aim is to undo the sanctions momentum. This is an astonishing statement. After all, the official objective of the sanctions are to get Iran back to the table.

If a new round of talks take place, there should be little doubt that negotiations will be tough. The divide between the two sides has grown as a result of the mutual escalation. And political space for the kind of sustained diplomacy needed to produce a breakthrough is in short supply in the US, Iran and the EU. Rather than a negotiation, we are likely to see yet another exchange of ultimatums. But if the EU repeats the mistake of 2010 and lets its mistrust overtake its judgement and imposes an oil embargo prior to the next meeting, then diplomacy will likely be dead on arrival.