The world order at the highest level relies on the nations themselves to behave, especially the largest ones because nobody has the practical power to enforce the decisions of the court in case defendants are in places where the court is not recognized. To USA not recognizing the court has always shown that they don't care about the crimes they commit.
Dead Comment
In some cases there is distrust from management on in-house employees or in some other cases they want to show quick results without distracting their teams from their planned tasks.
Of course there are the cases that managers have personal motives, either to add an extra (useless) achievement on their list or even worse to get referral fee or presents from the external consultancy.
We also need a paneuropean banking & tax system and ideally some paneuropean telephony (plus voip) and internet providers.