So much is happening on the surface at the moment that it can be difficult to notice certain undercurrents. Since the following story has gone almost unheeded in the Anglophone press, let me point at one especially suggestive current which could be glimpsed on the Continent this month.

Cast your mind back to March 2016 and you may remember a co-ordinated set of suicide bombings in Brussels: two at the airport, one at a metro station.