Garvan Walshe was National and International Security Policy Adviser to the Conservative Party until 2008. 

The four years of ignoring the civil war in Syria are over. Visiting a refugee camp in Lebanon, the Prime Minister said he wanted the people living there to go home. Very easy to say. Unbelievably difficult to do.

In the long term this will mean bringing the civil war in Syria to an end and replacing the Assad regime with a government capable of drawing support from all of Syria’s religious and ethnic groups, including the Sunni majority, with security forces and a power sharing leadership drawn from them all, and in which the important interests of regional powers including Iran, Turkey and the Sunni gulf states and the West, as well as the security of Jordan and Israel and the integrity of Lebanon, are secured. Even to state the outlines of a solution – a bigger version of Lebanon’s Taif accord – shows how difficult this will be, and how partial and unstable an arrangement it is likely to prove. Such an administration would have a better chance of confronting IS but would need external support for a long time, and could not avoid having a very fraught relationship with the de facto Kurdish state emerging to its north east.

A more immediate palliative will be some kind of limited humanitarian intervention. Parliament will soon be promised a vote on British involvement in Syria, blocked last time by Ed Miliband’s empty cynicism. Though it would be naive to suppose its timing will be unconnected with a chance to split Jeremy Corbyn’s Labour party – if this really had been so important, why wasn’t parliament recalled to debate it? – it provides a rare opportunity for this government to show it has a foreign policy that contributes to global security and perhaps even protect Syrian civilians from the barbarous war in which they are trapped.

There is however significant confusion about what the mission could achieve, and a danger of conflating quite different efforts, against IS on the one hand, and protecting them from the Assad regime on the other. Most Syrians live in the west of the country, in a line of cities that runs from Damascus up to Aleppo near the Turkish border. There, the regime has largely been able to deny the rebels control, by maintaining a regime of torture, mass disappearances and massacres in areas into which it can deploy ground forces and militias, and systematically bombarding areas from which it has had to withdraw, to prevent the rebels setting up an alternative government there. It is from this regime terror, and not IS, which rules in the sparsely populated desert, that most Syrians are currently fleeing.

The smallest expansion of British military activity would be to allow British aircraft to strike at IS targets on both sides of the Syrian border. This would certainly make the mission neater, but it would make little difference if it just meant that American or Gulf aircraft were focused more on Iraq to compensate for the shift in British air power to Syria. Conversely, if it was thought necessary to increase the intensity of the air campaign against IS this could be done by increasing British activity over Iraq without the need for a parliamentary vote. Other coalition planes, thereby freed up, could then concentrate on Syria.

Secondly, if it is indeed true that IS is planning a series of attacks on the UK, and that the plots in which the two men whose killing by drone was announced last week, a very different military mission would have to be considered. IS has until now concentrated on establishing state institutions in the Middle East – directly attacking what Islamist doctrine calls the “far enemy” would be a major change in strategy. If this change has occurred (a subject on which the jury is still out), a credible threat of major retaliation might be enough to deter them, but the government’s general reluctance to use significant military force, its parsimonious attitude to defence spending and the election of Jeremy Corbyn as Labour leader make conveying such a credible threat difficult.

If, however, the plans for terrorist attacks on the UK are not a significant part of their strategy, the current policy of intelligence-led assassinations is likely to be sufficient. Its communication must however change. IS attracts young men by promising them renown, adventure and a glorious death. Having your assassination announced by the Prime Minister in the House of Commons is the highest fame to which a British jihadi can aspire. The publicity that the Government has chosen to give his policy isn’t only unseemly, it’s also dangerous. Furthermore, the Government’s case will suffer unnecessarily from having to link every operation to such direct attacks – and also, like claims that Saddam Hussein had WMD, intelligence-based claims are vulnerable to being falsified. If major operations against IS are proposed, they will need to be based on more than intelligence reports if political support for them is to be sustained.

Operations against IS will not, of course alleviate the refugee crisis. Indeed if the pressure on IS is stepped up, more refugees will flee the intensified fighting, at least in the short to medium term. If the UK is to do more than pay for humanitarian aid, it would need to take part in missions to protect Syrians from Assad’s campaign of terror.

Two serious options have been canvassed: a no-fly zone and the establishment of safe areas. Both would be sizeable operations and require a coalition of Western states and friendly regional forces to prosecute. A no-fly zone over major concentrations of population outside regime control in Syria: northern Aleppo, Idlib and the Deraa in the south, could prevent the regime from using its most indiscriminate methods of terrorising rebel-controlled territory. Its establishment would however be far from trivial. Syria has an advanced air defence network, which has recently been reinforced by Russia. A full scale mission to deactivate it, though eminently feasible, would meet with Russian obstruction.

Nevertheless, an understanding that the no-fly zone would be restricted to protecting areas of civilian population and would not be aimed at weakening Syria’s other air defence capability, or interfering with Iranian operations in support of Assad, is conceivable. It could perhaps be reached if Damascus feared the destruction of its air defence network if it did not acquiesce in the limited no-fly zone.

Safe areas are a bigger challenge. It is possible to conceive of one in the south of the country, where there are signs that non-Islamist rebels are making progress. If this is indeed the case, such an area could provide a place for rebels to begin building the institutions of a new Syria, and for internally displaced Syrians to move to and start rebuilding something closer to normal lives. Protecting it would however require at least the credible threat of significant military force, beyond that needed for a no-fly zone. A safe area would not be viable unless people were actually safe there, not only from aerial attack but also from shelling and infiltration by Assad’s or IS’s militias. This task could only really be performed by the Jordanian military, supported by select specialist Western units that might, just about, fit the definition of “non-combat forces.” Other regional forces are neither available nor capable. Turkey’s current political crisis, and the strength of the Al-Qaeda-affiliated Nusra Front, render an equivalent zone in the north impossible for the time being.

Well designed military intervention could contribute to alleviating the worst of the horror that Syrians are suffering. But if it is to succeed it will require effort and resources closer to that applied in Kosovo in 1999 than in more recent operations like that in Libya. It would have been easier to intervene at the start of the rebellion, and still possible, though not without difficulty, in 2013. The choices are now more difficult. They will only get harder if we don’t face them now.