SAN FRANCISCO — On Tuesday, I was in Paris. The sun was shining. A great day for a walk. My sons and I hit the cobblestone streets and ticked off the usual suspects. Notre Dame. Tuileries Garden.

Eight suspects go on trial Monday (September 5) over the July 2016 attack in the Mediterranean city of Nice, where a radical Islamist killed 86 people by driving a truck into thousands of locals and ...