It doesn't pay to upset America endlessly (5)
I believe the answer is:
crime
'it doesn't pay' is the definition.
(I've seen this in another clue)
'upset america endlessly' is the wordplay.
'upset' indicates anagramming the letters.
'endlessly' means to look at the middle letters (the ends of the words are removed).
The centre of 'america' is 'meric'.
'meric' with letters rearranged gives 'CRIME'.
'to' is the link.
(Other definitions for crime that I've seen before include "Legal offence" , "Lawbreaking" , "Violation of law" , "Killing, for example" , "wrong-doing" .)