The 27 independent states that make up the European Union have diverse national criminal laws. Some of them have laws that consider an action a crime, while in other nation states it is not. Therefore it is easy to see how it could be a challenge to enforce criminal law among these members. This is where the strength of the body is tested. In circumstances when a crime has been committed that affect several states, and it is clearly not a crime in all the affected states, the union has to come together through their legislative body to decide how they will handle it.
The harmony and cooperativeness of the members of this union is shaken, because usually there is some decent on the method and penalty chosen. Thus the case usually end up coming before the EU Court of Justice. Their decision is final in these situations. There was a case of toxic waste spill that involved several member states in 2006. Spain did not have environmental violations in their laws as a crime. The other members came before the Legislative Commission, and had environmental damages made a crime in the EU. The case was taken before the EU Court of Justice, and was upheld as being a crime. In essence EU Criminal Law is still being established.