In Paris, church bells clang against the squawk of police sirens. Security forces of every stripe patrol the Jewish quarter in the Marais neighborhood, watching over tourists posing by the Louvre’s pyramid and hovering near the doors of the city’s landmark hotels and boutiques. Even as Paris prepares to empty out just as it does every August, leaving its cobbled streets to dwindling numbers of tourists, it is a city on guard.

The recent, deadly Bastille Day rampage through a seaside boulevard in Nice and the summary execution of an elderly Catholic priest in a village in Normandy have kept the country in the state of emergency President Francois Hollande instituted last November, following the coordinated attack in Paris that left 130 people dead. Heavily armed police now patrol the streets. “What can we do? Stay home?” asked one older man who declined to give his name, waiting in line by the Seine to collect boules for a game of pétanque. “We have to keep moving, keep living, otherwise, what is the point?”

France and the rest of Europe have endured this near state-of-siege before. Older Europeans can recall a time when communists, nationalists, anarchists, Islamists, and international criminals wrought havoc on the continent. Palestinian terrorists shattered the harmony of the 1972 Summer Olympics in Munich, taking hostageand murdering 11 Israeli athletes. Italian communists kidnapped and murdered a former prime minister in 1978. In 1988, Libyan terrorists brought down Pan Am flight 103 over Lockerbie, Scotland, killing 270 people. Through the 1970s and into the 1980s, warring Palestinian factions and Iranian revolutionaries turned Europe into a battleground for settling internal feuds and assassinating enemies, opening fire on the Rome check-in counter for the Israeli airline El Al, and hijacking planes. In France itself, an Algerian Islamist group that had fought the Algerian government during the civil war in 1991 bombed Paris metro stations, a Jewish school, and L’Arc de Triomphe. Hezbollah, as part of its declared aim to expel any French or American presence from Lebanon, conducted at least five bombings on French soil between 1985 and 1986. Armenian terrorists, seeking vengeance for the Armenian Genocide, struck the Orly airport in 1983, killing at least five people.

As Europe grapples with a wave of attacks either conducted or inspired by the Islamic State, the violence and tension the continent now faces have been dubbed a “new normal.” Yet it is a problem with a precedent. And how Europeans dealt with and ultimately overcame their terrorism problem in the past could bear lessons for how they deal with it in the future.

Despite the obvious ideological and strategic differences between ISIS and the threats of decades past, local law enforcement agencies across Europe can still draw on the tactical lessons of that previous age. To crack down on the possible movement of suspected bomb material by the Irish Republican Army (IRA), the Belfast police established checkpoints and searched cars and their drivers, for example. In the 1970s, authorities set up a “ring of steel” around the city center to prevent private cars from entering. Even then, of course, attacks persisted. ...