In the early hours of Thursday, March 26, a coalition of 10 Muslim countries led by Saudi Arabia launched airstrikes against Houthi rebel targets in Yemen, the Saudi kingdom's embattled southern neighbor. While Saudi Arabia does have a record of intervening militarily if it believes its neighbors are in significant danger of being overthrown and damaging Saudi interests - just look at the Bahraini Revolt in 2011 - it would be a tall claim indeed for anyone to prove that they could have forecast the magnitude and scale of this particular storm.When Saudi Arabia intervened on behalf of Bahraini King Hamad bin Isa al-Khalifa in March 2011, it was during the early, hotter days of the Arab Spring. Perhaps fearing a similar uprising in Saudi Arabia's restive Eastern Province, populated by Shiites and bordering Bahrain, a country with a majority Shiite population, the Saudis deployed the Peninsula Shield Force (PSF) after a request from King Hamad. In doing so, the Saudis could shrewdly argue that their action had broad backing from the Bahraini authorities themselves to the wider Arab Gulf region. The PSF is a multinational and regional rapid response force comprised of mostly Saudi soldiers supported by troops from the other states in the Gulf Cooperation Council (GCC), and therefore, this move was perceived as being supported by the governments of the GCC and not a unilateral Saudi move. In reality, however, PSF units deployed to Bahrain consisted of 1,000 Saudi soldiers and was supported by 500 police officers from the United Arab Emirates (UAE). The Shiite uprising, which most analysts agree was encouraged by Shiite Iran and likely based on sectarian identity rather than a broader civil rights movement, was swiftly crushed.However, the Bahraini protests cannot be compared to the power struggle and chaos that arose after the Arab Spring forced, at least temporarily, Yemen's then President Ali Abdullah Saleh from the power that he had held for over three decades, who had amassed $60 billion of embezzled Yemeni wealth as his retirement fund. Although the Shiite Houthi rebellion is nothing new as they have been active since at least 2004, Saleh's policies as well as direct Iranian support in the way of money, weapons and training allowed them to simultaneously outgun and outmaneuver the other Yemeni factions vying for power. While the Houthis received Iranian support, other Yemeni tribes and political organizations, predominantly from the Sunni majority, were disunited, fractious and did not have a regional backer to bolster them and bring them together. Complicating the issue further were the activities of al-Qaida in the Arabian Peninsula (AQAP), whose mere presence has the effect of dissuading potential backers from entering the fray and perhaps being branded as AQAP sympathizers. Thus, and unlike the Bahraini scenario, Yemen was largely left to deal with its problems on its own, opening up the opportunity for the more organized and better-armed Houthis to take control of the capital Sanaa on Sept. 21, 2014.Interestingly, however, this goes beyond the usual sectarian Sunni-Shiite conflict narrative. The simple fact that Iran is a country ruled by Shiite ayatollahs and that Saudi Arabia and the majority of other Muslim countries are predominantly Sunni obviously introduces an element of the oft-discussed sectarian divide that can be easily latched onto by casual observers. That being said, the issue here is primarily one of realpolitik and the balance of interests and power. Saudi Arabia is not reacting out of purely sectarian instincts with the objective of destroying a Shiite enemy and rival, but it feels genuinely threatened by Iranian power just as many Arab countries did under the days of the secular shah who ruled Iran prior to Ayatollah Ruhollah Khomeini after the 1979 revolution. Indeed, to this day Iran controls three islands in the Arabian Gulf that the shah unilaterally seized from the UAE in 1971, thus establishing a threatening Iranian presence near the Strait of Hormuz where 20 percent of the world's petroleum passes through.Since the invasion of Afghanistan in 2001, Iran has been steadily increasing its influence and power across the region. This became less subtle after Iran actively aided the West in the invasion of Iraq, a country dubbed the "Guard of the Eastern Gates" by other Arabs due to its role as Iran's traditional enemy and its strategic location acting as the first line of defense against the exportation of the Iranian revolution. Iran actively made its presence known, helping to install former Shiite Iraqi dissidents who were living in exile in Iran take power, such as the presently ruling Islamic Dawa Party. These moves insured an Iraqi government that was not only friendly to Iran, but subservient, and posed a threat to Saudi interests.Following this, Iran began to further extend the tendrils of its influence from Iraq through to Syria and even Lebanon, thereby forming what was popularly called the "Shiite Crescent" that stretched from Tehran to the Mediterranean Sea, all across the northern borders of Saudi Arabia and its allies. When the Bahraini crisis began unfolding, the Saudis could hardly ignore the fact that an Iranian controlled swathe of territory to its north would pose an even greater threat, particularly in conjunction with the high likelihood of revolt in its own Eastern Province, should the Bahraini Shiites succeed. In essence, the Saudis intervened in Bahrain to preserve their own internal security and integrity, not out of any notion of Sunni or Arab solidarity - otherwise it would have intervened in Iraq.Similarly, when the Houthis conquered most of Yemen late last year, it went beyond being unpalatable to the Saudis, as they now felt Iran was quite literally in their backyard. Some Iranian parliamentarians and senior military commanders even audaciously, and perhaps correctly, said that the so-called Islamic revolution of Iran had now spread to Yemen. If the Houthis managed to consolidate their rule and control over Yemen, Iran would have strategically surrounded Saudi Arabia to the north and south, posing a risk to any shipping passing through the Gulf of Aden, in addition to the shipping of goods and petroleum through the Strait of Hormuz, as previously mentioned. Such a situation is unacceptable to Saudi Arabia and untenable in the long-term.After having tried diplomatic means to try and shore up support for Yemeni President Abd Rabbuh Mansur Hadi and to agree to a peace deal, it started to become clear that the Saudis were losing their patience. Prince Saud al-Faisal, the Saudi foreign minister, issued a threat on March 23 saying that the Arab Gulf countries would act if the Yemen crisis was not solved peacefully. He further demanded that the Houthis withdraw their control over state institutions, which the Houthis roundly ignored while the Americans inexplicably increased tensions by removing Iran from the list of terror threats. The launch of Operation Decisive Storm showed that the Saudis could not only gather allies from North African Arab states, but also from Pakistan and countries in between. Turkey has now also lent its voice, if not its arms, to support the operation, further boosting the perception that this intervention is not just about Saudi power plays, but also about stabilization of a region wracked by wars and chaos that largely seem to be emanating from the halls of Iranian power.Operation Decisive Storm will not be as simple as the intervention in Bahrain. The Iranians learned their lesson well and have been equipping the Houthis with all manner of equipment, including aircraft and other heavy weapons, and so the danger to Saudi Arabia and allied forces is far greater. The Houthis are also experienced in fighting low-intensity conflicts, and so this problem cannot be settled by airpower alone and must involve a ground element. The Saudis could well finance and arm local Yemeni tribesmen to join the fight against the Houthis, which seems like the most logical option, and it is unlikely to fully commit its own ground forces. Iranian interference, subterfuge and expansionism have raised tensions to levels necessitating such reactions from other powers, and it is unclear how long this operation might continue. However long it lasts, one thing is clear - if it feels cornered, Saudi Arabia will act, and act forcefully.