(Wall Street Journal) Ron Prosor - As the terrorist threat evolves, so, too, must our response. In Nice, the use of a truck as the murder weapon shows how terrorism is constantly developing new ways to inflict mass casualties. Israel has bitter experience of this. The method of attack is painfully familiar. Since October, 44 terrorist attacks have used motor vehicles as a weapon against Israelis. In recent months, a new generation of terrorists radicalized on social media has launched more than 300 attacks in Israel using knives, guns and vehicles. Palestinian social media, and sometimes even official media, have published a flood of material glorifying the knife and the car as a weapon. The same is true of the jihadist groups murdering civilians in France and elsewhere around the world. In this digital age, terror cannot be met with an analog response. We need to keep up, and Israel has experience and expertise to share. Critics complain that such defensive actions compromise civil liberties and feed an atmosphere of fear. Yet the threat cannot be wished away, not when the ultimate civil liberty - the right to life without fear of death - is under attack. Preserving these freedoms and civil liberties while responding to terror is a challenge for any country, especially a democracy. In an age when the internet has turned yesterday's disturbed loner into today's radicalized sleeper cell, social-media companies must also take responsibility and play a role. Muslim, Christian and Jew must be engaged in the defeat of terrorism. Cooperation already takes place under the radar between Israel, Western countries and Arab states. In a fight that is as much a war of propaganda as it is of weapons, the open involvement of Arab and Muslim countries would send a powerful and timely message.