In the fight against terrorism, national agencies keep full control over their police forces, security and intelligence agencies and judicial authorities. ↗
Look at Iraq; look at Afghanistan, where at great personal physical risk people have gone to the polls and have rejected the appeal from Bin Laden and his allies to stay at home. ↗
Police forces collect information to be used in a public court to get people convicted. Security services gather information that does not necessarily lead to people being prosecuted and in many cases needs to remain confidential. ↗