<p>The UK governments proposal to join the air campaign against Islamic State (Isis) in Syria is built on the argument that such action would disrupt its ability to organise attacks in Europe, while containing the extremist group by denying it territory and access to finance primarily through oil exports. The experience of the US-led coalition so far, and the counter-terrorist campaign against al-Qaeda before that, offer evidence that at least some of these goals can be achieved. But they also suggest campaigns conducted mainly from the air carry significant risks of backfiring.</p> <p><strong>Will bombing disrupt Isiss ability to carry out terrorist attacks in Europe?</strong></p> <p>The prime ministers <a href="https://www.scribd.com/fullscreen/291209463?access_key=key-wWmOF3IlMYn56JB9fgXx&amp;allow_share=true&amp;escape=false&amp;show_recommendations=false&amp;view_mode=slideshow">memorandum to the Foreign Affairs Select Committee</a>, seeking to address MPs scepticism, said: This military effort helps put Isil [Isis] on the defensive, suppressing their ability to conduct external attacks against the UK and our friends and allies.</p> <p>The investigation into the Paris attacks showed that at least half the perpetrators had undergone some kind of centrally organised training with Isis.</p> <p>The experience of the fight against al-Qaida suggests that precise targeting of training camps and leaders reduced its capacity to strike western capitals. A trove of documents US navy Seals recovered at Osama bin Ladens compound showed that drone strikes had made it near impossible for al-Qaida to host and train foreign fighters in the main area under its control, the Federally Administered Tribal Areas (Fata) in western Pakistan.</p> <p>This concern about drones affected al-Qaidas ability to train westerners in Fata, where all the drone strikes have been targeted. It also dissuaded westerners from going to Fata to train, said Peter Bergen, director of the international security programme of the New America Foundation and author of a series of books on al-Qaida.</p> <p>However, there are also signs that Isis has learned from al-Qaidas mistakes, and now avoids structured training camps, preferring to live and organise in residential buildings among civilians.</p> <p>In Raqqa, Deir Ezzor and Mosul, Isis is living almost totally among civilians, so you cant hit them, said Rami Abdurrahman, head of the Syrian Observatory for Human Rights. He pointed out that thousands of foreign jihadists had managed to travel to and from Syria for the past few years through Turkey and questioned the wisdom of now trying to stop jihadists with bombs when they could have been stopped with tighter border controls.</p> <p>The Paris conspirators, including the presumed mastermind, Abdelhamid Abaaoud, were able to travel between Belgium, France and Syria while the US-led airstrikes targeting Isis command and control were in full swing.</p> <p><strong>Can bombing contain Isis?</strong></p> <p>In David Camerons words: The coalitions military strategy aims to stop [Isiss] advance through the air campaign, to strike them in their heartland and to put them under pressure by continuing to degrade and dismantle their economic and military capability.</p> <p>US-led airstrikes helped stop Isis capturing key strategic points such as Kobane on the Turkish border, and the Kurdish stronghold of Irbil. In neighbouring Iraq, they were instrumental in preventing the fall of Baghdad when Isiss power was at its zenith. UK air support also played a role in the liberation of the Iraqi town of Sinjar by Kurdish Peshmerga forces.</p> <p>Counter-terrorism experts say that such defeats damage Isiss international appeal to foreign jihadists, which depends on the image of a constantly expanding caliphate. </p> <p>However, further gains against Isis will require something that has so far eluded the western coalition, a working alliance with other Sunni rebel groups in Syria. Camerons memorandum claimed that there are 70,000 Syrian opposition fighters on the ground who do not belong to opposition groups. Experts say the number is credible but note that for most of them, the first priority is to fight the Syrian regime.</p> <p> Hassan Hassan, a Syria expert at the Chatham House thinktank and co-author of Isis: Inside the Army of Terror, said that persuading other Sunni armed groups to fight Isis as well as the regime may ultimately be the key to success, but that requires a great deal of local knowledge and political commitment.</p> <aside class="element element-rich-link element--thumbnail"> <p> <span>Related: </span><a href="http://www.theguardian.com/community/2015/nov/27/how-do-you-feel-about-military-action-in-syria">How do you feel about military action in Syria?</a> </p> </aside>  <p>The answer is not dropping more bombs, Hassan said. The answer is to find a way to support these groups on the ground. Its not about money or even weapons. It is about helping them with tactics and an overall strategy that has been missing.</p> <p>He argued that the expensive US efforts to build an anti-Isis rebel movement failed because it worked with the wrong people and lacked long-term political commitment. The success of any British military contribution, Hassan added, will lie in the UKs ability to break out of the constraints of Washingtons current strategy.</p> <p>The recent emphasis on striking tankers carrying Isis oil exports is likely to dent the groups vast financial resources but may not affect its immediate fighting capacity. Hassan said Isis scored its most significant victories before it captured the oil fields.</p> <p><strong>Could bombing Isis backfire?</strong></p> <p>Airstrikes on Raqqa on Thursday are reported to have killed at least 12 people, including five children, when bombs fell near a school. It was not clear whether the bombs were dropped by Russian, American or French planes.</p> <p>The number of civilian casualties from Russian bombardment is far higher than the number caused by American and French airstrikes, said Wael Aleji, spokesman for the Syrian Network for Human Rights. This can be attributed to technology. The Russians use more dumb bombs and have less advanced guidance systems.<br /></p> <p>In his memorandum, Cameron pointed to the enhanced precision of the UKs Brimstone missile as one of the contributions Britain can make to the air campaign. But avoiding civilian casualties will also depend on good intelligence. One of the worst civilian tolls attributed by human rights activists to a US strike was on 1 May <a href="http://www.theguardian.com/world/2015/may/02/death-toll-syria-climbs-us-led-air-strike">near Aleppo</a>, where more than 60 civilians were said to have been killed, perhaps more than half of them children. Abdurrahman said: We think they got the wrong information. They thought it was Isis, but it wasnt.</p> <p>As it becomes harder to find genuine Isis targets, as the terrorist group gets better at melting in with the surrounding population, the civilian toll is likely to rise. And Syrians on the receiving end are unlikely to make the distinction between British warplanes and Russian bombers sent by Assads chief ally.</p> <p>This is likely to generate support for Isis, or at least create indifference among local people, Hassan said. These are the risks of unintended consequences. </p>