“Israel is a key piece in the puzzle” to solving the world’s growing terrorism problem, US Brig. Gen. (ret.) Russell Howard said Wednesday at the IDC Herzliya Conference on Counter-Terrorism on the university’s campus.Howard made the comment as part of a panel on learning lessons from recent major terror attacks around the world.He expressed confidence about the US ability’s to cope with the ongoing terror threat, but serious concern that Europe was not up to the job.The retired general also said that Europe has a bigger problem as in 2015 it had around 5,000 European citizens fighting in Iraq and Syria, meaning it could have 5,000 battle-hardened terrorists returning back to its shores. In contrast, he put the number of US citizens fighting in the same area at a much more manageable 200.Another panelist, Editor of the CTC Sentinel Paul Cruickshank, put the number of European-citizen-fighter who might return as high as 6,000-9,000.Friedrich Grommes, Germany’s Head of Directorate TE, International Terrorism and International Organized Crime, described the terror threat as evolving from earlier periods.In earlier periods, a big concern was “sleeper cells,” terrorists “planted” in a country long ago to rise through a country’s ranks, living normal-seeming lives, until they reached the right position and moment to strike. Grommes said that currently “there are no real sleeper cells” as many terrorists move fast, hitting targets in foreign countries as soon as they have done minimal surveillance.The German intelligence czar said this gives Western intelligence a much shorter period in which to identify and catch terrorists, which requires legislation to give them stronger means, especially in accessing private data.He also expressed concern about the complexity of the large volume of Syrian migrants who have arrived in Germany, many of who may start out as harmless, but could be radicalized by ISIS while stuck without work during the long wait for their requests for refugee status to be recognized.IDC Dean of the Lauder School of Government Boaz Ganor provided one positive update, noting that in the Facebook era it is finally possible to track and stop some lone wolf terrorists by tracking postings which are pro-terror groups, In contrast, prior to Facebook posts, such lone wolves went completely under the radar since they had no formal communications with other terrorists which could be spied on.In a later panel on the dilemmas that law-abiding countries face when up against asymmetric terrorists who ignore the laws of war, former IDF international law division head Col. (res.) Daniel Reisner started with the controversial statement that, “there is no leg requirement in the laws of war for a proportionate response” to being attacked.”Next, he asked about the demand for proportionality - “where is this coming from?” He said that some of it related to the bad public picture of so many Palestinian casualties in the 2014 Gaza war compared to a much smaller number of Israeli casualties, but also implied that there were serious legal scholars who were demanding proportional responses in overall fighting of wars who had other agendas.Reisner’s criticism was at the forest level of general force brought to bear over the course of an entire war. All of this is separate from the set law that a specific attack which harms civilians within a war must not cause disproportionate harm compared to the military advantage the one specific attack was designed to achieve.He said “international law doesn’t have answers” to the large and highly-relevant questions he raised. Responding, Emory international law professor Laurie Blank disagreed, saying that “we have well-established frameworks for the use of force,” while acknowledging that often applying those rules to the current challenges of fighting non-state terror entities was not an easy task.