Western news coverage tends to depict Israel as the chief advocate for a hard line against the Iranian nuclear program.
But the concerns of the Gulf states, in particular Saudi Arabia, are of equal or greater urgency.
Since the foundation of the Kingdom of Saudi Arabia, the US has performed the role of protector for Riyadh. The departure of the British from the Gulf area in the early 1970s meant that the small Gulf monarchies also came to depend on the US for protection.
Washington has bases up and down the Arab side of the Gulf.
But the mere presence of these bases no longer bring a feeling of security. The Arab monarchs and emirs of the Gulf Cooperation Council countries (Saudi Arabia, Kuwait, Bahrain, Oman, Qatar and United Arab Emirates) are watching with dismay as US President Barack Obama's administration seeks rapprochement with Tehran.
It is Saudi Arabia which is most concerned. Riyadh is engaged in a struggle to contain and set back Iranian expansion across the region.
The Wikileaks revelations in 2010 made clear the extent of Saudi and Gulf concerns regarding Iran.
King Abdullah was famously quoted as demanding that the US "cut off the head of the snake" by launching military strikes against Iran's nuclear program.
King Hamad bin Isa al-Khalifa of Bahrain, according to the cables, also argued for Western military action against the program.
Riyadh's central concern is that the US simply fails to grasp the extent and the seriousness of Iran's regional project. This, in their view, is part of a more general naivete – which has produced failed US policy in key areas of the Middle East over the last three years.
The US decision to abandon Hosni Mubarak of Egypt was for the Saudis an early indication of the problem. This has been compounded by the failure to lend support to the military coup of Gen. Abdel Fattah al-Sisi, a close ally of Riyadh. Washington's failure to organize properly to frustrate the Iranian effort to preserve President Bashar Assad in Syria is an additional telling example.
The Muslim Brotherhood victories of the Arab Spring deeply worried the Saudis. But in the course of 2013, these have mostly been reversed.
In Tunisia, Egypt and the Syrian rebellion, the Muslim Brotherhood is now eclipsed. Saudi money and machinations have played a central role in this.
But Saudi money will not be enough to turn back the Iranians.
For that, Riyadh needs more powerful allies. Hence the acute fear that the Americans are no longer willing to play this role.
The Saudis' view of Iran gibes in all essential details with that of Israel. This commonality was openly expressed by influential Saudi columnist Tariq Alhomayed, in a recent interview with the Weekly Standard magazine: "Israel is the most important player in the Middle East right now regarding Iran... They drew the red line on Iran, and that makes everyone in the region happy."
The Saudis see Tehran's nuclear ambition as part of a more general drive for regional domination in two directions – westwards towards the Mediterranean, and southwards towards the Gulf. This is a project which is already underway.
To the west, Iran is in the process of turning Nouri al-Maliki's Iraq into a client, or at least a closely allied state. Iran is fighting tooth and nail to keep its ally Assad in place in Damascus. His fall would end the dream of a contiguous pro-Iranian line from western Afghanistan to the Mediterranean Sea.
In the absence of the US, the Saudis have themselves tried to do the heavy lifting of support for the Syrian insurgency. It isn't working.
Assad has consolidated his position in the course of 2013, and is now beginning to claw back territory from the rebels.
In the Gulf area, the Saudis have watched as Iran continues to back opposition movements in Bahrain, Kuwait, north Yemen and in eastern Saudi Arabia itself.
For the Saudis, as for Israel, a nuclear capacity would clear the way for a massive increase in subversive activities of this kind.
A nuclear Iran, they fear, would be able to entice or bully the small Gulf states to come under its umbrella. This would then give Iran the ability to set or influence global oil prices, and thus blackmail both neighboring countries and global powers.
Riyadh's bond with the US is not about to break. The Saudis have nowhere else to go; there is no other power currently able to project military power into the Gulf.
The Obama administration, meanwhile, is keen to assure the Saudis that its military presence is there to stay, and their concerns are unfounded.
Simultaneously, however, the Saudis see the Iranians winning in Syria and Iraq, engaging in subversion across the Gulf, and moving full speed ahead toward a nuclear capacity – with their traditional partners blithely reassuring them there is nothing to worry about.
The result? A recent BBC report suggested the Saudis have readied a nuclear option for themselves, in the form of an agreement with Pakistan that would supply nuclear weapons to Riyadh if Iran were to acquire a nuclear capability.
There may be substance to these reports. Or they may be part of a desperate PR campaign by the Saudis to seek to inform the US of the cost of an Iran-Washington rapprochement.
Either way, they are testimony to just how bad things have got between Washington and its closest Arab allies, as a result of the lenient tone toward Iran, and the broader process of disengagement from the region adopted by the current administration over the last three years.