Stability in Afghanistan will require tens of thousands more troops costing billions more dollars than Nato envisioned at a fateful 2012 summit, according to a new Pentagon-sponsored review.The review, released Thursday and conducted by the nonpartisan think tank CNA at the behest of the Pentagon’s policy directorate, found that the Taliban insurgency is likely to swell in the years following the upcoming US and Nato military withdrawal, sharply challenging expectations set at Nato’s May 2012 summit in Chicago. The review also saw widespread deficiencies in Nato’s planning for Afghanistan manpower, logistics, air support and ministerial strength.The CNA review panel, which included a former Marine Corps commandant and US Army chief of staff, found that thepersistent Taliban insurgency will mount an increased threat to the Afghan government for years after the envisaged Nato withdrawal, and require a force substantially larger and more expensive than Nato has planned. The CNA team’s prediction of an increased Taliban threat to Afghanistan through 2018, supported by a recent US intelligence assessment, “stands in direct contradiction to the assumption of a reduced insurgent threat made at the Chicago Summit,” the report states.Persistent weaknesses in the Afghan security forces are not only a matter of manpower, the CNA team found. “Systemic gaps in capability” remain, including in intelligence, air power, mobility and logistics. The US military plans on spending what could be its final year in Afghanistan addressing those gaps. The CNA team also advises the Pentagon to keep international military advisers in the Afghanistan ministries of defense and interior through “at least” 2018 to mitigate long-term problems, including corruption and incompetence – something that will not be possible unless Karzai’s successor signs the so-called Bilateral Security Agreement. “Our analysis suggests that the absence of these advisors has the potential to undermine the ANSF’s combat effectiveness over the time-frame of this study, thereby imparting additional risk to the US policy goal for Afghanistan", the CNA team found.“We conclude that this force is not likely to defeat the Taliban militarily, but that if it can hold against the Taliban insurgency through 2018, the likelihood of a negotiated settlement to the war will increase", the CNA review said.The CNA panel was contracted by the former undersecretary of defense for policy, Jim Miller, following a congressional mandate for an Afghanistan security sector review.