Make an argument saying that the restrictions in civil liberties after 9/11 (such as those in the Patriot Act) violate the underlying principles of American democracy.
To make this argument, we must first define the underlying principles of our democracy. We must say that freedom of speech and association underlie our democracy. We must also say that freedom from governmental searches and seizures are underlying principles of our system.
More importantly, we have to take a strict line on these principles. We have to argue that the restrictions have been excessive. We have to say, for example, that allowing the government to secretly search a home (even with a warrant) is a serious infringement upon the principle that we should be safe from searches and seizures. By saying this, we are saying that these restrictions are serious violations of the underlying principles of our system.
We never have complete freedom of speech or association. Our freedom of speech is always restricted to some degree. We are always subject to some searches and seizures. Therefore, in order to argue that the recent restriction violate the underlying principles of our democracy, we have to argue that these restrictions are excessive and therefore dangerous.