give somebody enough rope
US /ɡɪv ˈsʌmˌbɑːdi ɪˈnʌf roʊp/
UK /ɡɪv ˈsʌmˌbɑːdi ɪˈnʌf roʊp/

1.
to allow someone to do whatever they want, in the belief that they will eventually get into trouble or fail
:
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Just give him enough rope, and he'll eventually mess things up on his own.
•
The manager decided to give the new employee enough rope to see if he could handle the responsibility.