May I mention one restriction which I find quite dangerous if one looks into the future. Many States interpret this to mean that only during the decolonization process the right of self-determination enjoys precedence over the sanctity of borders. Even States with a long democratic tradition have difficulties to accept the idea that their population has the right to put the existing borders in question. One of the arguments is that earlier generations have already made the choice to belong to this State or this nation and that the following generations are therefore bound by this decision. With few exceptions present borders have not been established in a democratic process.
Every democracy accepts the idea that constitutions and laws can be changed in a democratic process.
In a democracy the majority decides. History shows that even in well established democracies the majority can suppress a minority. If there is not a clearly defined right of self-determination for a minority the rule of law and with it democracy can be the first victims. As we have seen this can easily lead to a collapse of the State either through civil war or some other mechanism. Restrictions on democracy threaten not only democracy itself but the State which seeks its legitimation in democracy.