Bruce Hoffman in a radio interview, which whilst under 4 mins, is split into three portions:http://www.scpr.org/programs/take-tw...01/whybelgium/

Raffaello Pantucci (RUSI) via the FT and a pessimistic viewpoint, whcih ends with:
The Brussels attacks will also play badly against the backdrop of Europe’s migration crisis. It will not be entirely surprising if elements close to the recent attacks found ways of slipping into the country alongside refugees from the Middle East. An already tense situation in Europe will grow more fraught, and this will have inevitable political ramifications too. This is the biggest problem with which security planners will have to contend. It is often said that the best response to a terrorist threat is to keep calm and carry on. This is sage advice but in the face of a network that appears able to strike with impunity, and a political environment growing more toxic by the day, it will be ever harder for security forces and politicians to ensure that Europe maintains its values in the face of the terrorist threat from within.
Link:http://www.ft.com/cms/s/0/a6459d5a-f...#axzz43gC1qcBT