National concern (7)
I believe the answer is:
subject
I believe this is a double definition.
'national' is the first definition.
('subject' can be a synonym of 'national')
'concern' is the second definition.
(thesaurus)
(Other definitions for subject that I've seen before include "Expose; field of study" , "guinea pig" , "topic of conversation?" , "Musical theme" , "Theme, topic" .)