The latest atrocity by the world’s leading Islamist terrorist group, Islamic State, is certainly not going to be among the last, unless an emergency international effort is mounted to meet its threat.Among the condolences to the victims, a statement by the Wiesenthal Center put this into perspective: Such horrific, coordinated mass murders will only end when there is a sustained global strategy in place to destroy ISIS’s leadership and infrastructure in the Middle East and to root out their terrorist support systems and cells wherever they are found.” The center also urged social media companies to block terrorists from using their services.There is no denying the constant increase in terrorist attacks throughout the world in the name of delusional religious fanatics out to establish a world caliphate. The entire world is being held hostage to violence by a lunatic organization intent upon world domination. Call it a religious war.Its most recent battlefield was the Belgian capital’s Zaventem airport and Maelbeek metro station. Belgium is a natural choice for Islamist terrorism. For one thing, more Belgians have left Europe to enlist with Islamic State per capita than from any other country. Belgian law enforcement is overwhelmed by the volume of open terrorism investigations. The some 300 Belgians estimated to have fought in Islamist ranks in Syria have made Belgium a focus of concern in France and other neighbors over its security capabilities.On Wednesday, Belgian Prime Minister Charles Michel hosted a pre-scheduled visit by French Premier Manuel Valls, who declared: “We are at war.”“What we had feared has come to pass,” Michel said, vowing to meet the threat.Indeed, a direct link has been established between the Paris bombings in November in which 130 people were murdered and 368 others were wounded, and the Belgian attacks. The Paris assaults were apparently organized from Brussels, according to French Finance Minister Michel Sapin, who accused “certain leaders” of “naiveté” in holding back from security crackdowns in their Muslim communities.That was a bit much for Belgian Foreign Minister Didier Reynders, who suggested that each country should deal with its own social problems, pointing out that France also has rough districts where Muslims become radicalized.A prime suspect in Tuesday’s Brussels bombings, Najim Laachraoui, was reported arrested by the Belgian newspaper DH on Wednesday. He was allegedly filmed by a security camera accompanying two suicide bombers to the airport counter on Tuesday; they were identified as Khalid and Brahim El Bakraoui, two brothers from Brussels known as petty criminals but not terrorists.It is probably no coincidence that the Brussels bombings closely followed the capture of Salah Abdeslam, one of the leaders of the November 2015 Paris terrorism rampage, in the Brussels suburb of Molenbeek last Friday.Laachraoui has been identified as an ISIS bomb-maker.His DNA was found in apartments used by the Paris attackers last year, Belgian officials said on Monday, adding that he had traveled to Hungary in September with Abdeslam.The relationship uncovered between the Islamists Laachraoui and Abdeslam hint of a widespread terrorist infrastructure that has been allowed to take root and flourish in the capitals of Europe. It is also no coincidence that all the suspects so far hail from Molenbeek, which is known in law enforcement circles as “Europe’s terrorism capital.”When police entered Molenbeek to arrest Abdeslam, members of the immigrant community greeted them with a hail of bottles, rocks and garbage, identifying more with a wanted terrorist than with the land that gave them refuge.Everyone agrees that allowing terrorists loaded with explosives to enter an airport is a colossal mistake. The world’s airport authorities would do well to learn why Ben-Gurion is considered the world’s safest. One reason is the layered security: concentric rings of checks from the outermost perimeter to the check-in counter, including armed guards, undercover security personnel, personal interviews, and even bomb-sniffing dogs.Islamic State has warned of “black days” coming to those countries fighting it in Syria and Iraq. But while Belgium’s warplanes are indeed flying sorties with the coalition air forces, it is but one of the several available targets.