The tensions between the ruling regime and the rebels in Yemen had been slowly simmering away but now they have reached boiling point and the consequent civil war that has erupted is bound to have deep regional and international repercussions. The Houthi rebels, known as Ansar Allah, started their insurgency in 2004 against the regime of Ali Abdullah Saleh, at a time when the US invasion of Iraq was still underway. The rebels laid siege to the capital of Sanaa last September and, since then, have taken over control of large chunks of territory in the country. The rebels have a strong Shia persuasion and are believed to have the support of the regime in Tehran, which has the Sunni Saudi Arabia worried over increasing Iranian control in the Middle East.From the perspective of the Wahhabi Kingdom, the situation at the borders does indeed look daunting. In bordering Iraq, Iranian security forces are helping fight against encroachment by Islamic State (IS). In neighbouring Syria, Iran is involved in providing military assistance through its Revolutionary Guard to Bashar Al-Assad’s regime. And let us not forget what the Iranian-backed Hezbollah is capable of doing in Lebanon. Now, with Houthi rebels taking control in the Yemeni cities of Sanaa and Aden, the Saudis have decided to take matters into their own hands. In order to stop rebel advances towards other cities and to send a strong message to Iran, the Saudis have put together a coalition of 10 or so Arab states and have launched air strikes in Yemen. The rebels are fighting back and the situation in Yemen has gone from bad to worse in a matter of days. State machinery has stalled, leading to widespread strife and panic. At the time these words were being written, hundreds of stranded Pakistanis also risk being caught in the whirlwind of violence engulfing Yemen. Efforts are already underway to evacuate our countrymen from the Yemeni capital and one hopes that they will bear fruition soon.But, as much as the advance of the rebel forces towards Aden is being made out into this critical ‘red line’ whose crossing had the Saudi jets start bombardment of territories lying close to the southern Saudi border, there is perhaps another dimension to the crisis as well. The US and Iran are coming tantalisingly close to a nuclear deal that will see Tehran’s nuclear programme kept in check but ultimately legitimised. Such acceptance can bear numerous rewards in the field of energy generation as well as increase any country’s international stature, a possibility that is perhaps a bit too hard for the Saudis to swallow. As the veteran journalist Robert Fisk notes, perhaps what provoked the Saudis into their extraordinary adventure in Yemen was not the approach of Houthis towards Aden but the approach of the US-Iranian agreement at Lausanne. In this way, the US, much to its un-liking, is inexorably bound up in this crisis. By supporting Saudi Arabia, they risk letting all efforts over détente with Iran go to waste. And if they side with the Iranians on Yemen, they risk facing the ire of the Saudis’ oil tactics, as well as cementing in the negative the US’s image in the Kingdom.The Saudis have asked Pakistan to join the coalition and provide military assistance as well, to which the Pakistani Prime Minister (PM) has responded in a hasty and enthusiastic manner. The PM’s statement that threats to Saudi sovereignty will invoke strong responses from Pakistan has had the saner voices in the country worried sick about getting unnecessarily involved in another unending conflict. Defence Minister Khwaja Asif has since then taken over damage control responsibilities and has clarified that Pakistan is not despatching troops to Saudi Arabia — not yet at least. The decision to get involved in Yemen ultimately depends on the military leadership and, unlike Nawaz Sharif, who owes the Saudis a solid favour or three, the army is bound to undertake a cost-benefit analysis of the situation before embarking on any uncalculated adventures.In many ways, the story of the recent conflict in Yemen is that of favours that have come back to haunt the givers and the receivers alike. The Saudis called in a favour with the US in the first Gulf war, which destabilised much of the region and kick-stared al-Qaeda’s campaign against the ‘infidel west’. Similarly, Pakistan, a country that has benefited a lot on account of large inflows of Saudi aid, must now make good on its promises and prove its loyalty to the Saudis. The US learnt the hard way that ignoring Afghanistan after its initial victories was a tactical nightmare and if Pakistan decides to go the same route and divert resources away from the anti-terrorism operation, it could wreak unimaginable havoc.Additionally, the Middle East stands as a stark reminder of how favours can have unintended consequences that come full circle in a devastating way. There are no free lunches in international relations and Pakistan — much like the US — will have to make peace with the lesser of the two evils. In deciding to do so, both countries are bound to end up siding with the devil they know, which will have serious repercussions. In the coming days, we are sure to see a lot of grandstanding over the call to join the Saudis in their quest but rest assured that the final decision in this regard was made the moment we accepted the first dollars as gifts from the Kingdom. They say that a favour will kill you faster than a bullet; let us at least hope that this is not the case this time round. The author is a freelance columnist with degrees in political science and international relations