President in wilderness (4)
I believe the answer is:
bush
I believe this clue is a double definition.
'president' is the first definition.
(two US presidents have been called Bush)
'wilderness' is the second definition.
(bush is a kind of wilderness)
'in' acts as a link.
(Other definitions for bush that I've seen before include "Shrub; Kate --, singer" , "Outback" , "ex-president" , "Scrub" , "Shrub; hole lining" .)