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Gates at military bases are often manned by unarmed or lightly armed guards, wooden swing gates, and not much else. "Terrorists do not care much about rules, signs, or procedures," Faddis writes. "If your mechanism for requiring a vehicle to stop is a hand gesture to the driver, you are likely to secure compliance from all the law abiding people...It is, however, not likely that a terrorist driving a vehicle loaded with explosives and traveling at a high rate of speed is going to pay a whole lot of attention to your frantic motions for him to come to a complete stop and state his business."
Example: In 2007, the FBI arrested six radical Islamist men and charged them with plotting to enter Fort Dix, N.J. and kill as many soldiers as possible with machine guns.