Riyadh takes a gamble in Yemen

The Iranian diplomatic position is at the mercy of 100 Saudi fighter jets and 150,000 Saudi soldiers.

On Wednesday, the Saudi ambassador to the United States, Abdel al-Jubeir, announced the Gulf Cooperation Council (GCC) had answered Yemeni President Abed Rabbo Mansour Hadi's call for intervention.

The ambassador's announcement in Washington is seen as having the green light from the US administration.

US support for "Decisive Storm" against the Iran-backed Houthi movement - who took over Yemen and consequently threatened the balance of power in the Gulf - reaffirms the fact that the Iranians were heading into the latest round of talks with a strong hand.

Now, the Iranian diplomatic position is at the mercy of 100 Saudi fighter jets, 150,000 Saudi soldiers on hold, and other Saudi and Egyptian naval units.

Iran's upper hand

In the US, Obama's insistence on a diplomatic "solution" to Iran's nuclear ambitions drew his party and his administration into a critical political confrontation with his opponents.

In that sense, Iran knows that Obama can no longer afford to leave the negotiating table empty-handed.

If George W Bush's legacy of foreign policy success was Iraq, Obama's was Yemen, at some point.

Now that Yemen is a lost cause, his administration's foreign policy success or failure is even more dependent on a deal with Iran. The "what if" in the case of a no agreement could be costly to the US president.

On the other side of the negotiating table, Iran expected to arrive at the last round of talks with significant military accomplishments in Iraq, Syria and Yemen.

Iranian regional policies have given it an edge over US allies in the region. Iran has exploited military and political indecisiveness from Arab regional powers and consequently reached the southern coasts of the Gulf through the Houthis' advances.

This could have helped the Islamic Republic's position in the political dimension of the nuclear deal, whereby Western powers are inclined to acknowledge a greater role for Iran in the future of the Middle East.

Iran appears to be a stable country with significant military capabilities and sectarian soft power, a status the West not only cannot ignore, but also actually needs.

Turning the tide in Tehran

Going by the famous saying "better late than never", Iran's rivals in the Middle East have come together, with Israel, to "change the facts on the ground" having failed to turn the tide on the negotiating table.

In Syria, Assad's forces, fighting alongside Hizballah, are advancing south toward the Golan Heights. Rebel groups are struggling to contain that offensive, facing a shortage of resources and fighters. But the tide is turning on Iran and its allies in the north.

As the Gulf countries formed the "Decisive Storm" coalition in Yemen, rebel groups in Syria formed the "Fattah Army" coalition - including al-Nusra Front, Jund al-Aqsa, Jaish al-Sunna, Liwa al-Haqq, Ajnad al-Sham, and Faynad al-Sham -  to take back the strategic city of Idlib in Syria's north.

The city lies between Aleppo, Hama and Homs. The capture of Idlib from Assad's troops and securing the northern routes would be a strategic blow for Iran's position in Syria.

In Yemen, the Iranian-backed Houthis have a history of military confrontation with Saudi Arabia. However, the support the Houthis get from Iran is unmatched in their history of struggle with local Yemeni forces and Gulf countries alike.

Capitalising on this line of support, Houthis took over Sanaa and moved swiftly toward the south, reaching Aden this week. Houthis rejected all calls for negotiations, stormed political conferences across the country and enforced their rule at gunpoint.

In response, Saudi Arabia launched a "shock and awe" offensive on Sanaa on the first night of the operation. On its first day, Egyptian naval vessels were already at the coastal city of Aden, and Houthi-held air and military bases, radar, and political offices were pounded by Saudi jets.

The Saudi-led offensive seems, so far, to be uniting Yemenis rather than dividing them further.

The Saudi-led offensive seems, so far, to be uniting Yemenis rather than dividing them further, however.

Numerous prominent critics of the Houthis have raised concerns regarding "Decisive Storm".

The last thing most Yemenis want at the moment is to further internationalise a local conflict. To be fair, this feeling has yet to become a Yemeni consensus. But as history repeats itself in Yemen, a most certain conclusion will be regret.

The 'Decisive Storm' of a nuclear deal

It will take a while to know how decisive "Decisive Storm" is.

It is not only dependent on the Saudi-led military operation, but also on the outcomes of the nuclear talks with Iran. The operation launched in Yemen might well serve as a distraction for Iran's rivals, while Iran seals the deal with the West.

The same operation, however, might be decisive enough to complicate the talks even further and stall the diplomatic momentum. Two years ago, a Saudi offensive in Yemen could have possibly blown up the nuclear talks.

What is certain now is that this week will definitely prove to be "decisive".