The former United Kingdom prime minister Tony Blair and some United States politicians are making the case for armed intervention against the ISIL (Islamic State of Iraq and the Levant) insurgents in Iraq, even if in most cases they are not recommending American and British troops on the ground. Barack Obama’s administration is, for now, cautious. But one element being entirely missed out from the argument is the possibility that ISIL actually wants intervention. It might be useful, then, to look at the situation from the perspective of an ISIL strategist attempting to chart the way ahead in light of its advance. 

ISIL has had a substantial presence in western districts of Mosul for some time, but the speed of the Iraqi army’s collapse around 10-11 June probably went far beyond the group's immediate expectations. There have been atrocities, but ISIL also has support - indeed, some refugee movements have been motivated by fear not of the ISIL presence but of counter-attacks on Mosul by the Iraqi air-force. As a result, many are now returning to the city.

This means that Iraqi government forces are highly unlikely to be able to regain Mosul in the weeks and months ahead. This also applies to Fallujah, though the far more economically important town of Baiji is a different matter – its oil-refinery and power-station may make this is the one significant centre the Iraqi government might try to recover.

In any case the collapse of Mosul has enabled ISIL to acquire considerable monetary resources (possibly exceeding US$400 million in banknotes) and substantial equipment and munitions. Moreover, the rapid transfer of arms and equipment from Syria indicates that ISIL is already planning consolidation.

It may now be that ISIL has only one more immediate aim: an attempt to overrun Balad air-base north of Baghdad. US trainers and other personnel have been hastily evacuated from Balad, leaving extensive stores of munitions and equipment that would enhance ISIL’s longer-term capabilities. That, rather than Baghdad, may well be a priority for ISIL’s limited forces.

The picture then is that beyond Balad and a few other towns, and an increased presence in parts of western Baghdad, major further gains by ISIL are highly unlikely.  For one thing, gaining control of predominantly Shi’a areas is much harder than taking over predominantly Sunni districts; for another, Iranian support will ensure that Baghdad remains secure in government hands.

Two related issues must also be noted. The first is that ISIL planners are among the most experienced paramilitary tacticians anywhere in the world, let alone the region - not least because of the experience they have gained in years of combat against western counterinsurgency forces.  

The second is the modest numbers of paramilitary fighters available to them - perhaps 10,000 in all. It is true that their rapid recent gains may draw some support from local clan groups, but the impact of this is likely to be limited numerically and to affect only the immediate area. In addition, Bashar al-Assad’s regime may use ISIL’s concentration of forces in Iraq to attack some areas in Syria controlled by the group.

All this points to the consolidation of ISIL’s extraordinary gains in the weeks ahead, even once some modest tactical withdrawals are taken into account.

The west’s temptation

More broadly, a priority for ISIL until the end of 2014 will be to recruit more experienced paramilitaries from across the region. The group will also want to attract volunteers from wider diasporas, though the latter require months of acclimatization and training to have much impact.

In the longer term, ISIL planners are looking to secure and consolidate an Islamist caliphate stretching across large parts of northern Syria and northwest Iraq. This will require increased support from abroad in the form of financial and material aid as well as the boost in personnel. 

The greatest help in advancing these aims would be open western military intervention in any form, even if restricted primarily to the use of armed drones.

Any such intervention will aid ISIL’s ability to propagandize such intervention as yet another example of the western ‘far enemy’ at work. The latter would encompass any Israeli action in Syria, allowing a propagandist theme used widely in 2003-06 to be recharged. This focused to great effect on the notion that Israeli aid for the US operations in Iraq (which was little acknowledged in the west but well-known in the region) was part of a ‘crusader-Zionist plot’ to great effect.

It is thus wise to face up to the distinct possibility that ISIL will endeavour in the period ahead to incite western and Israeli military intervention, in the process countering Obama’s reluctance to take this route. 

For this reason alone, quite apart from any others, such intervention would be a grave mistake. By contrast, avoiding the temptation would at least limit ISIL’s ability to further strengthen itself and thereby enhance its dangerous capabilities in the coming months.

This does not in any way help in trying to determine what are the best ways forward and what roles western states can most usefully play. On this question, though, it can be said that Iran, Saudi Arabia and Turkey are hugely more important than these states currently recognize.

This article was originally published in openDemocracy.

Paul Rogers is a professor in the department of peace studies at Bradford University, England. He is openDemocracy’s international-security editor and he writes monthly briefings for the Oxford Research Group.  Read his briefing on the Iraq crisis for the Oxford Research Group.