On May 13, coordinated suicide bombings struck three churches in the Indonesian city of Surabaya; a fourth bombing occurred at the local police station the next day. Islamic State (IS) claimed responsibility for the attacks. To Ilan Berman and James Clad, the incident is indicative of a growing threat to the overwhelmingly Muslim country:

Indonesian Islam has long contained important cultural and ideological barriers to intolerance. . . . Despite variations within the 3,000-mile archipelago, Indonesia’s bedrock culture, especially in Java, reflects and reinforces coexistence among faiths, as well as tolerance for differing worldviews. Since the late 1990s, Indonesia’s democratic institutions have flourished in a diverse milieu in which self-described “Islamic” parties are free to contend. . . .

But is this delicate balance eroding? . . . The past couple of years have indeed offered worrying signs that Islamist groups and ideologies have gained influence. This includes, notably, the rise of Hizb-ut Tahrir Indonesia, a radical group complicit in the political ferment that surrounded last year’s hotly contested gubernatorial elections in Jakarta. The group is now formally banned by President Joko Widodo’s national government. . . .

[A]s of last fall some 700 Indonesians were estimated to have joined the ranks of Islamic State in Iraq and Syria. Those radicalized elements are now returning home, with devastating effect—all of the perpetrators of the Surabaya attacks were “alumni” of IS’s Middle Eastern caliphate. . . .

These trends make Indonesia an inviting target for Islamic State. With its decline in the Middle East, the terrorist group has made Southeast Asia a target of opportunity. Last fall, Islamic militants affiliated with IS waged a pitched but ultimately unsuccessful battle for the southern Philippine city of Marawi. As May’s bloody events in Surabaya make plain, similar radicals have now set their sights on Indonesia as well. Their goals are clear: to undermine the country’s religious moderation and exploit its shifting domestic scene in order to promote their own extreme worldview. And, like elsewhere, their successes will be measured by pluralism’s failure.

On Tuesday, a Hizballah drone attack injured three people in northern Israel. The next day, another attack, targeting an IDF base, injured eighteen people, six of them seriously, in Arab al-Amshe, also in the north. This second attack involved the simultaneous use of drones carrying explosives and guided antitank missiles. In both cases, the defensive systems that performed so successfully last weekend failed to stop the drones and missiles. Ron Ben-Yishai has a straightforward explanation as to why: the Lebanon-backed terrorist group is getting better at evading Israel defenses. He explains the three basis systems used to pilot these unmanned aircraft, and their practical effects:

These systems allow drones to act similarly to fighter jets, using “dead zones”—areas not visible to radar or other optical detection—to approach targets. They fly low initially, then ascend just before crashing and detonating on the target. The terrain of southern Lebanon is particularly conducive to such attacks.

But this requires skills that the terror group has honed over months of fighting against Israel. The latest attacks involved a large drone capable of carrying over 50 kg (110 lbs.) of explosives. The terrorists have likely analyzed Israel’s alert and interception systems, recognizing that shooting down their drones requires early detection to allow sufficient time for launching interceptors.

The IDF tries to detect any incoming drones on its radar, as it had done prior to the war. Despite Hizballah’s learning curve, the IDF’s technological edge offers an advantage. However, the military must recognize that any measure it takes is quickly observed and analyzed, and even the most effective defenses can be incomplete. The terrain near the Lebanon-Israel border continues to pose a challenge, necessitating technological solutions and significant financial investment.