State is firmly put in place (5)
I believe the answer is:
posit
This clue is a double definition.
'state' is the first definition.
(I've seen this before)
'firmly put in place' is the second definition.
(posit can mean to position)
'is' acts as a link.
(Other definitions for posit that I've seen before include "state" , "Assume as fact for argument's sake" , "Put forward; place" , "Suppose" , "Lay down as principle" .)