Last week Pentagon officials revealed that the number of ISIS fighters in Libya has grown to between 5000 and 6500 – more than double the number estimated last year.

In a previous post ('Why Libya peace talks are crucial in the fight against ISIS') I talked about the rise of ISIS in Libya and the need for a political settlement that could pave the way for cooperation between pragmatic military factions fighting ISIS. Such a deal was reached in Morocco last month, but so far a government of national unity proposed under the UN-backed plan has been rejected by Libya's rival parliaments over allocation of ministries and the transfer of power over military appointments.

If a viable unity government does not materialise in coming weeks, it is likely that an ad hoc coalition made up of the US, France, Italy and the UK will decide to intervene militarily. Last week, President Obama instructed his National Security Council to counter efforts by ISIS to expand to Libya, including by military action. Such action — likely to be more limited in scale than the 2011 intervention — would likely consist of an aerial campaign complemented by Special Forces, and intelligence liaison with Libyan armed groups on the ground.

While there are compelling reasons to prevent the metastasising of ISIS beyond its primary base in Iraq and Syria, earlier Western interventions offer three lessons that would suggest a military operation in Libya, however limited, is fraught with risk.

First, while Western countries focus on how, why and under what conditions they should participate in military interventions, far too little attention is paid to how such an intervention would end. It is true that a light military footprint can prevent some of the pitfalls of large-scale interventions such as Iraq and Afghanistan, but nevertheless, such interventions achieve little in the absence of a political settlement, risking the type of mission creep Western countries are trying to avoid.

Secondly, limited interventions of the kind currently being considered by the international community in Libya will, according to one voice from the field, 'work indirectly through partners and thus are most effective when security institutions exist or a patchwork of local armed actors shares enough common ground that it can be leveraged to promote stability.' 

There is no such common ground in the region of Sirte, an ISIS stronghold and the likely target of Western military action. Both rival Libyan governments have rejected the presence of ISIS in the region, but their military factions have been fighting each other in and around Sirte. US Special Forces have been deployed to Libya in recent months to liaise with these factions, assess capabilities, and identify local factions to support in an anti-ISIS surge.

Yet analysts have pointed out that singling out factions to work against ISIS will be challenging due to 'overlapping alliances, tribal connections, and shared interests among them.' For example, the Libyan Petroleum Facilities Guard, which is fighting Wilayat Tarablus (ISIS) in the Sirte region, is commanded by Ibrahim Al-Jadran, who is the brother of an ISIS commander and who has been accused by the head of Libya's National Oil Corporation, Mustafa Sanalla, of siphoning oil to ISIS.

The 'city-state' of Misrata, crucial to ISIS's expansion plans, has also deployed its powerful militias to Sirte to fight ISIS, and has repeatedly asked for military assistance from the US. It would provide Misrata with the international legitimacy it seeks to emerge as a powerbroker in a future political settlement. More importantly, its local interests could pave the way for an anti-ISIS alliance with General Haftar — who leads forces aligned with Libya’s internationally recognised government in Tobruk — pending the supply of weapons to his forces. However, it would further fragment the Dawn camp — a coalition of Islamist militias supporting Libya’s Tripoli government — to which the Misrata factions are allied, and inflame intra-Islamist conflict in Western Libya. Crucially, a rift between Misrata and the Ansar al-Sharia-aligned Islamist factions which dominate General National Congress (Dawn’s political body), would jeopardise UN efforts to establish a unity government.

Thirdly, as we have seen in Afghanistan, Syria and Iraq, a strategic rapprochement between key regional players is crucial to the success of a Western intervention. In Libya, both Algeria and Egypt support (to various degrees) the internationally recognised government and share similar cross-border security concerns. However, they diverge on the means to improve stability and security. Egypt has supplied Haftar’s forces with weapons and has twice conducted air strikes on targets in Tripoli and Derna, while Algeria, in line with its doctrine of military non-intervention, has advocated a political solution and firmly backed the efforts of UN Special Representative Martin Kobler.

A Western intervention would embolden Egypt to ramp up its military support for Operation Dignity — Haftar’s anti-Islamist military offensive in East Libya — and alienate Algeria, an indispensable broker of stability in the Sahel region and an influential power over major tribes in the western regions of Libya, which have long been marginalised due to their loyalty to Gadaffi, but whose role will be decisive in the formation of a national unity government.

Photo by: Godong/UIG via Getty Images