Married conditions apply in this country (6,6)
I believe the answer is:
'apply in this country' is the definition.
'United States' can be an answer for 'country' (United States is an example). I'm unsure of the rest of the definition.
'married conditions' is the wordplay.
'married' becomes 'united' (similar in meaning).
'conditions' becomes 'states' (I've seen this in another clue).
Can you help me to learn more?
(Other definitions for united states that I've seen before include "National federation" , "Country, capital Washington DC" .)