As IS control erodes in Iraq and Syria, about half the foreign fighters from the UK, Sweden, and Denmark have returned. IS kept detailed records of fighters, and captured computers and cell phones have helped those fighting IS to create a membership profile. Nearly 20,000 names have been shared with Interpol. It is highly likely that, as the territorial caliphate shrinks, its leadership will look to supporters overseas, including returnees, to keep the brand alive. Rory Stewart, a government minister, caused a stir when he said, ‘They are a serious danger to us, and unfortunately the only way of dealing with them will be, in almost every case, to kill them.’ Meanwhile, Max Hill QC, who advises the government on such matters, says that former IS fighters should be reintegrated into society. See: