I agree a Democracy Makes it harder to detain suspects. Although I had no problem in Moscow, foreigners were carefully watched. In Alanta things were messy with little control. I was push by others when trying to take the photo of the torch relay. No police intervene or control the area.
I am sure Oswald was a suspect as many others. But a democratic government can not arrest on suspicion. We ha a cast here today where a father who was on a police watch list kill his son. The police could not arrest him before the crime and then all they did was shot him. Democracy is messy but still the best form of government.