Adopt, support (7)
I believe the answer is:
espouse
I believe this is a double definition.
'adopt' is the first definition.
(I know that adopt can be written as espouse)
'support' is the second definition.
(as in espousing or supporting an idea)
(Other definitions for espouse that I've seen before include "Adopt or support, say a cause" , "See opus to support a cause" , "help!" , "See opus (anag)" , "Give support to - see soup (anag)" .)