No one should meddle with this internationally sensitive case (10,3)
I believe the answer is:
diplomatic bag
'no one should meddle with this internationally sensitive' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'case' is the wordplay.
I cannot quite see how this works, but
'case' could be 'bag' (bag is a kind of case) and 'bag' is found within the answer.
The remaining letters 'diplomatic' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for diplomatic bag that I've seen before include "One taking post abroad" , "Embassy's mail container" , "Embassy mail sack" , "Embassy mail pouch" .)