Yemen has been central in the calculation of Saudi Arabia. In the 1960s, Saudi Arab and Egypt sent in troops to beef up the opposing sides in the Yemen civil war. Then Saudi Arabia backed the immate system of the Zaidi Shias while Egypt rooted for the overthrow of the feudal order represented by the Zaidi Shia.

However, in 2015, Egypt and Saudi Arabia are singing from the same hymn sheet. As a result, the current conflict has acquired wider regional and global resonance. This is because of a number of recent political developments in the region.

One, the US-Saudi relations are not as warm as they once were. This freeze is traceable to decreasing US reliance on Saudi oil and the US reluctance to get involved in the region as opposed to its past knee-jerk intervention in the Middle East. The US interventions in Iraq are illustrative of this.

Two, the crisis in Syria and Iraq has aligned the interest of US and Iran in so far as the ISIS is concerned.

Third, Iran has reached a far-reaching nuclear deal with major world powers, which restores Iran politically and economically on the regional and world scene.

Fourth, the game for regional pre-eminence between the Gulf Cooperation Council (GCC), Arab countries, Iran, Turkey and Israel has warmed up. This regional geo political reordering is occurring against the backdrop of a Yemen internally divided along regional, sectarian, and tribal lines.

Over the past decade or so these divisions have sharpened due to the collapse of the political order lorded over by Abdullah Saleh -- and supported by GCC and the US -- in the wake of the Arab Spring. The new political order supplanted has only served to exacerbate the long-running sectarian and regional forces vying for equal share of power.

The Saudi-devised and GCC-endorsed political order, currently represented by Mansour Hadi, has been at the centre of the current turmoil in Yemen. This is the bald backstory to the current crisis.

With the Saudi decision to bomb Yemen, various scenarios are panning out. Since March 26, Saudi strikes have failed to stem the advance of the Houthis. This means that ground troops will have to be committed to change the balance of power on the ground in favour of the Saudi-backed regime.

Right now the Houthis and Saleh forces, well-trained and well-armed, are still holding out and making modest advances in the face of airstrikes. If the ground forces are committed, resistance is most likely to grow aided by battle-hardened Houthis/Saleh combine and general disgust engendered by the Saudi airstrikes.

With the prospect of a full-scale civil war looming and the airstrikes continuing, humanitarian crisis has reached worrying proportions. The residents of Aden have been without water for a few weeks now. Despite the appeal of Red Cross and the Russian efforts to organise Security Council meeting to discuss the ceasefire, the humanitarian crisis is worsening.

With this intervention Saudi Arabia is seeking to establish itself as the regional policeman. This is necessitated by the US reluctance to get involved in the Middle East quagmire. Yet the newly arrogated role of the Middle East arbiter has all sorts of implication for the region. Yemeni intervention, apart from reorganising the domestic political arrangements, is also a way to show that Saudi can manage regional conflicts without the US military support.

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Saudi Arabia has bolstered this impression by putting together a joint Arab force along the lines of the NATO. The joint Arab force will have the undesired effect of militarising the region and escalating the arms race.

Yemeni intervention has also placed Egypt back in the spotlight as an influential player in the region. This has resulted in increased aid flows to Egypt. Egypt is also the driving force behind the idea of the Joint Arab force which is being envisaged to counter the twin threats of growing Iranian influence and the ISIS.

With this, Egypt’s role as regional storm trooper looks set to grow. This intervention has also lent legitimacy to the military dictatorship of Al-Fateh Al-Sisi. The new military ruler of Egypt is already burnishing his anti al-Qaeda credentials by bombing extremists in Libya.

Saudi strikes have also united Qatari and Saudi Arabian goals in relation to the new order in the Middle East. So far, Saudi Arabia and Qatar have pursued divergent goals in Egypt, with Saudi Arabia backing the new military dictatorship and Qatar rooting for Muslim Brotherhood. The new understanding also stems from the growing warmth between the two royal families.

Saudi intervention has also opened up maladroitly papered-over political divisions within Yemen. The deployment of ground troops is certain to entrench the already existing deep divisions along religious, regional, and tribal lines. The net result could be a prolonged civil war to which Yemen is no stranger. However, this time around, the civil war will become more complicated as a result of the rise of new Saudi-backed political party Islah and al-Qaeda.

Saudi coalition’s intervention has also raised profound questions about the threat of al-Qaeda and ISIS in the region. Aggressive efforts to contain the Houthis will lead to the consolidation of al-Qaeda. This will sour relations between Saudi Arabia and US, which is deeply concerned about the growth of al-Qaeda in Yemen as elsewhere.

Conversely, Saudi and Israeli understanding on Iran has grown. Press and media report have hinted at growing convergence between Israel and Saudi Arabia on the Iranian nuclear threat. If true, this convergence has all sorts of implications for the Middle East politics which has so far remained focused on the pivot of Arab-Israeli axis.

Moreover, the Saudi opposition to the Iranian nuclear deal may also lead to regional nuclear arms race. Saudi’s attempts to acquire nuclear bombs are already circulating in some press reports. More worryingly, if Iran becomes the new driver of the Middle East politics then the much dreaded spectre of new politics emerging along the Shia-Sunni divide cannot be wished away. The reconstruction of the Middle East along inter-Muslim rivalry rather than Arab-Israeli axis is of huge significance for the future.