Islamist terrorism in Europe is on the rise, as evidenced by the Charlie Hebdo shootings in Paris, the grisly beheading of a UK serviceman walking the streets of London in 2013, and the shooting spree in Toulouse and Montauban. Whereas the death of Osama bin Laden and the advent of the 'Arab Spring' fed expectations that international jihadism was a spent force, Europe has faced an increase in terrorist plots over the past few years. In addition, there are growing security concerns over the fallout of the Syrian conflict, and its sizeable contingents of battle-hardened European...