The coordinated rail attacks that disrupted train travel in France on three high-speed lines Friday morning occurred despite intensive security precautions put into effect leading up to the Olympics, which officially begin Friday night.
Not only have police and soldiers poured into Paris over the past week to sweep and secure the Olympic sites and the center of the city along the Seine, where the opening ceremony is scheduled to take place, but they visited the homes of people they considered potential threats and imposed what amounts to house arrest on 155 of them.