Put into effect (5)
(Other definitions for apply that I've seen before include "suit" , "Put in for job" , "Put (eg, paint) on" , "concentrate" , "Ask for, a position perhaps" .)
'put into effect' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for enact that I've seen before include "Establish by statute" , "Put into practice" , "Establish by law - perform" , "Decree" , "Play one's part" .)
'put into effect' is the definition.
(enforcing is a kind of putting into effect)
This is all the clue.
(Other definitions for enforce that I've seen before include "Impose by necessity" , "Compel or impose obedience, say to law" , "Compel adherence to (a law)" , "Compel observation of" , "exercise" .)