someone's hands are tied
US /ˈsʌm.wʌnz hændz ɑːr taɪd/
UK /ˈsʌm.wʌnz hændz ɑːr taɪd/

1.
to be unable to act freely or to help in a particular situation because of rules, laws, or other restrictions
:
•
I'd love to help you, but my hands are tied by company policy.
•
The government claims its hands are tied by international agreements.