Tuesday's terrorist attacks in Brussels raise two key questions: Were they related to Salah Abdeslam's arrest last week and, if so, how? It seems unlikely that the attacks were revenge for the capture of Abdeslam, the top suspect in last year's Paris attacks, because not only was he a relative nonentity in Islamic State circles but also a symbolic liability to the brand: Here is a man who reportedly walked away from a martyrdom operation, leaving his colleagues to do all the dirty work, so to speak. In other words, he isn't someone whom any other militant is likely to have sacrificed himself for. In fact, it is probable that, after Abdeslam's arrest, he would have been regarded as a threat to the wider network of terrorists in Belgium.