People saw this coming.

In the aftermath of the attack in lower Manhattan on Tuesday, I was reminded of a conversation I had almost a year ago with a veteran counterterrorism chief in Madrid. He had just written a report to his superiors warning about the urgent threat that terrorists would use trucks or cars to mow people down in public places. It wasn’t a sudden flash of insight. Months earlier, a Tunisian deliveryman with a history of mental illness had driven a large cargo truck into a crowd of Bastille Day celebrants in Nice, France, killing 84 people and injuring 450 more. In its edition last November, the main online propaganda magazine used by the Islamic State, Rumiyah, had put out a call for more such attacks, offering tips on how to carry them out.

“The writer very explicitly urges a Nice-style model,” the Spanish official said. “He even gives details about the kind of truck – double axle and double wheel, to do more damage. He urges attacks on public gatherings: political rallies, pedestrian zones, celebrations of the holidays. They are really pushing the mass-casualty, lone-actor model.”

The Spaniard, a burly veteran of the fight against Basque and Islamist terrorists, would only discuss the intelligence on the condition that he not be named. But he told me that information from around Europe indicated that Germany looked especially vulnerable.

Following the template

A week after we spoke, another Tunisian driving a hijacked tractor-trailer careened through a Christmas market in Berlin, leaving 12 dead and 55 injured. That assailant, who was shot dead by Italian police in Milan days afterward, had also pledged allegiance to the Islamic State.

Colleagues praised the Spanish counter-terrorism official for his foresight. But some officials in Spain didn’t heed the warnings. The national police had strongly urged Barcelona to gird itself against vehicle attacks. However, city officials resisted a recommendation to install vehicle barricades in the bustling and emblematic Ramblas promenade in the heart of the city, an obvious target. Mayor Ada Colau said such defences clashed with Barcelona’s identity as “a city of liberty”.

On August 17, a 22-year-old Moroccan who had grown up near Barcelona drove a rented van down the Ramblas, running over pedestrians. By the time police caught or killed him and others in his terror cell, which was inspired and possibly supported by the Islamic State, the casualty count was 16 dead.

New York has arguably been at the forefront of cities in the West in protecting its freedom with heightened security. Since the September 11 attacks, parts of downtown Manhattan have been extensively retrofitted. In areas around the World Trade Center site, Wall Street and the large cluster of government buildings nearby, metal barricades and police checkpoints have become part of the landscape.

But most of the city has not been armoured in the same way, and parts of it have remained open. The West Side Highway bike path that was attacked on Tuesday, while no one’s idea of a symbolic or political target, is a small monument to the cyclists whose presence in the city has grown steadily in recent years. And it passes only blocks away from the World Trade Center Memorial.

The Halloween attack will renew debate about examining vulnerabilities and reinforcing defenses. But as horrifying as it was, the larger realities of the battlefield have not changed, counter-terrorism experts say. The Islamic State has been substantially weakened. Like the Spanish counter-terror official, many of his colleagues in Europe and the United States see the emerging trend of lone-actor vehicle attacks as a sign of weakness, not strength.

Weakened infrastructure

The Islamic State showed what may have been its peak capacity for mayhem in the West in November 2015. A team of well-armed gunmen and bombers, most Europeans who had been trained and directed by masterminds in Syria, struck multiple targets in Paris, killed 130 people and spread havoc in a world capital. Surviving plotters took refuge in their native Brussels, eluded capture for four months, and pulled off suicide bombings at the airport in the Belgian capital, killing another 32 people. Those frenetic five months epitomised the menace of the Islamic State, its hyper-violent culture that swept through neighborhoods of Europe like a drug, its formidable infrastructure for recruiting and deploying killers.

In the past year and a half, however, a combination of aggressive counterterror enforcement in the West and military action in the Middle East has battered the group. The Islamic State is in danger of losing its sanctuary, war chest, propaganda apparatus and operational networks. Thousands of fighters have been killed in fierce urban battles, dying in the ruins of the so-called caliphate. The threat of sophisticated, mass-casualty attacks has diminished in Europe, intelligence officials say.

“Now there’s a lot more amateurism,” another senior European security official told me several months ago. “It has to be said the attacks in Paris were the result of a perfect storm. There were well-trained returning jihadis, some of them combat veterans, local support, an enormous flow of refugees that they took advantage of [to travel from Syria]. Now there could still be a lightning bolt, but I hope the perfect storm doesn’t repeat itself.”

And the threat of a Paris-style plot was always lower in the United States, counter-terror officials say, because we don’t have the same combustible mix of problems facing Europe. The United States doesn’t have to confront a blurring of criminal and extremist populations, vast Muslim communities afflicted with unprecedented levels of radicalisation, or the kind of weak border enforcement that makes nations such as Greece vulnerable to infiltration by terrorists.

Series of attacks

Before New York, however, there was a series of smaller attacks in the West by individuals or small groups, most of them using vehicles or knives. They were typically inspired by Islamic State propaganda or, in a few cases, by jihadis in Syria providing remote direction and encouragement over social media and encrypted telecommunications. The trend is hard to stop precisely because of its simplicity.

The accused New York attacker, Sayfullo Saipov, apparently followed a playbook disseminated by Rumiyah magazine in November of last year. The article singled out the Macy’s Thanksgiving Day parade as an “excellent target”.

“Though being an essential part of modern life, very few actually comprehend the deadly and destructive capability of the motor vehicle and its capacity of reaping large numbers of casualties if used in a premeditated manner,” the article said.

The brutal scenario was enacted on the campus of Ohio State University soon after the magazine edition appeared. A Somali immigrant student went on a spree with a car and a knife. No one died except him. But then came the Berlin Christmas market attack; the Westminster car and knife attack in London in March (five dead); a Stockholm truck attack in April (five dead); the London Bridge van and knife attack in June (seven dead); the van and knife attacks in Barcelona and the nearby beach town of Cambrils (16 dead), and finally, yesterday’s mass murder on the bike path near New York City’s Stuyvesant High School.

Like most of the previous attackers, Saipov used a rented vehicle. Like most of the others, he wasn’t completely unknown. It’s been reported that he came up on the radar screen of the FBI in connection to a previous investigation. That isn’t necessarily a surprise or a scandal. In 2001, the longtime French counter-terror judge Jean-Louis Bruguiere told me it was very rare to encounter a case of terrorism in which the suspects were not already in a case file or an intelligence report somewhere. His words have been confirmed repeatedly since then.

In the London attacks, the terrorists continued their rampages on foot with knives. Saipov, in contrast, didn’t hurt anyone else once his truck crashed because his weapons consisted only of pellet and paintball guns. Given the ready supply of firearms in the United States, his limited armament suggests a relatively primitive plot and a lack of a support network.

In Europe, the gun laws are stricter and terrorists have had a harder time obtaining firearms. A French intelligence chief told me this year about arms traffickers in the housing projects of Paris refusing to sell to extremists because of the risk of going to prison on terrorism charges.

Change of tactics

ISIS’s change in tactics also reveals the new obstacles to training. In 2014 and 2015, thousands of aspiring Western jihadis trekked via Turkey to Syria. They trained with weapons and explosives and then returned home, often without being detected. The days of such unfettered movement back and forth appear to be over. Although you can study bomb-making techniques on the internet, the real thing isn’t that easy. The attack with the rented van in the Barcelona area was improvised by youthful plotters after their leader and other suspects died in the explosion of their bomb factory in an abandoned house.

It seems clear in the Barcelona case that the authorities could have done more in terms of prevention. Not only did the city fail to install barriers, the regional and national counter-terror forces didn’t detect the terrorist cell, even though its leader was an imam with a criminal record for drug and immigrant tracking, had previous contact with terrorists in prison, and had been the subject of a query from police in Belgium to police in Barcelona.

The city of New York has developed a muscular counter-terror apparatus at strategic as well as tactical levels. There’s the FBI-led counterterror task force, the NYPD’s counterterror division, and the NYPD intelligence unit whose reach extends into neighboring states and to overseas capitals, where liaison officers gather intelligence and develop alliances.

Nonetheless, yesterday’s attacker slipped through. In the aftermath, New Yorkers refused to let the violence interfere with trick or treating or the Halloween parade. That’s heartening to US and European counter-terror officials, who say the United States has better defenses than Europe in many ways – but also a vulnerability at the political level.

In an interview with ProPublica earlier this year, the former director of the intelligence community’s National Counterterrorism Center, Matthew Olsen, warned against proposed extreme restrictions on Muslim refugees and immigrants and the tone of the political debate about terrorism. He and other experts say that one of America’s great strengths has been its ability to integrate immigrants, including Muslims, and to avoid provoking the kind of resentment and alienation that have fed radicalization in many European nations.

This article first appeared on ProPublica.