Europeans don't generally understand that many things that Americans do have the purpose of protecting the individual from the state, whereas the inhabitants of the Old Continent think that they are done for different reasons.
Two of the most illustrative and important cases of this misunderstanding are the right to bear arms and the secular state.
Europeans usually think that the US Constitution's right to bear arms has to do with individual protection from criminality and violence from other individuals. In reality, its main goal is to protect the citizen from the power of the state.
Without this constitutionally-enshrined right only the state, through the armed forces and the police, would be be authorized to have the use of arms, and this is a huge source of power and control.
It's reminiscent of the origin of the expression 'crossing the Rubicon'. The Rubicon is a river in Northern Italy which is sufficiently distant from Rome to have been elected by the ancient Roman Republic as the safe boundary, the defining line which nobody could cross with an army. The Romans knew only too well that weapons are a great source of power.
You must have an enormous trust in a government to allow it to be the only entity to be permitted to carry arms.
In my second example, Europeans in their majority believe that the secular state serves the purpose to protect the state from the power of the Church, whereas the opposite is true: the separation between Church and state has the role of protecting the Church from the power of the state.