Protect, maintain (8)
I believe the answer is:
preserve
This clue is a double definition.
'protect' is the first definition.
(I know that preserve is a more specific form of the action protect)
'maintain' is the second definition.
(I know that maintain can be written as preserve)
(Other definitions for preserve that I've seen before include "Guard" , "Protect; jam" , "Keep alive, maintain" , "Keep alive; jam" , "Particular interest" .)