Engineers the people into a form of government (8)
I believe the answer is:
republic
'a form of government' is the definition.
(republic is a kind of form of government)
'engineers the people' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'the people' becomes 'public' (public is a kind of people**).
're'+'public'='REPUBLIC'
'into' is the link.
(Other definitions for republic that I've seen before include "Country with no king" , "The political system is an epic blur" , "Plato's ideal state" , "Political system of government by the people" , "France, for example, is one" .)