"Soft targets" are what security and intelligence officials call those busy civilian places where someone might set off a bomb undetected – airports, sporting events, nightspots, concerts – and gain attention by provoking a panicked response.
That term took on a sickening new meaning on Monday, when a Manchester arena full of children, young teenage girls and their parents was struck by a bomb packed with nails and bolts in a terrorist attack that killed at least 22 people, some as young as eight years old.
Horrific terrorist attacks aimed at unguarded civilians enjoying themselves are nothing new to Britain. They are especially familiar in Manchester, where many still feel the trauma of a much larger terrorist bomb that struck a shopping mall in the same part of Manchester in 1996 amid a wave of Irish Republican Army terror – the largest explosion in Britain since the Second World War – which miraculously killed nobody but injured 212 people, some severely, and left the city's downtown core in wreckage.
However, even at a time when terror attacks on civilians have once again become part of European life, there was something different about Monday's Manchester attack. It marked a new threshold of terrorism, and is likely to change British life in important ways.
First, it is now abundantly clear that the Middle Eastern terrorist army that calls itself Islamic State is able to persuade its European admirers to give up their lives to strike even the most innocent of targets.
In the past few years, Europe has been struck by a series of highly traumatizing soft-target attacks, in Paris, Brussels, Nice, Berlin and elsewhere, all carried out by Europeans loyal to the group (also known as ISIS or ISIL).
A rise in Western security meant that the traditional Islamist targets of symbolically significant government, military and business centres had become too hard to hit, and the terrorist group evidently realized that it can gain attention and sow fear by striking daily European life.
The group's official channels eagerly claimed credit for the attack, though it is doubtful they were aware of the attacker or his plans beforehand. Islamic State's English-language Internet service boasted that a "soldier of the Khilafah [caliphate] managed to place explosive devices in the midst of the gatherings of the crusaders … in response to their transgressions against the lands of Muslims." It referred to the arena full of preteens as a "shameless concert arena."
This means that daily life is going to become more difficult for many Britons, and possibly for people further abroad. Routine events such as concerts are going to be subject to much higher security, and detailed X-ray checks and searches will become a routine inconvenience for almost anyone's day-to-day life (as they were during the peak years of the IRA crisis).
Second, it means that there are a huge number of potential suspects who officials fear could carry out a similar attack.
The Manchester terrorist, if early reports are accurate, was a British man known to the police. This fits the pattern of almost all the recent European attacks: They have been carried out by Europeans, often – but far from always – from Muslim families, who have sometimes roused law-enforcement suspicions but have not been linked to organized terrorist networks or been considered prime targets for surveillance.
"We value our society, we talk about freedom of assembly, freedom of expression, and all this sort of thing, and we really do want to preserve those values against the attacks or terrorism, and if we're following around 1,000 people or something I think we're losing those values," Richard Barrett, a former global terrorism operations director at the spy agency MI6, said in a BBC radio interview Tuesday morning. "I don't think anyone's expecting the security services or police to monitor the population here on the scale of perhaps what was done in East Germany."
The problem is that there are hundreds such people, far more than agencies can monitor (it can take dozens of full-time officials to keep tabs on one suspect individual).
Mr. Barrett described the scope of the problem: "You've got the returnees from Iraq and Syria, there are over 400 of those, there are all the people who wanted to go to Iraq or Syria but were stopped, we heard some time ago there were 600 of those, so already you're up to 1,000 before you even start on the people who live here and maybe never expressed any or didn't knowingly express any intention to go to Syria, so what do you do about that?"
The upshot is that British policing and intelligence efforts are likely to become even more invasive, intrusive and disquieting. And this change is occurring weeks before Britain heads to an already-fraught election (all parties agreed to suspend campaigning after Monday). Beyond the immediate grief and horror, there is a real sense that Manchester is going to change things for the worse.