Enforcer
An enforcer was one who compelled another to obey a law or directive.
In 2155, Josiah proclaimed that the presence of 5-10,000 unregistered aliens on Earth was due to United Earth's policy and the Starfleet enforcers of same. (ENT: "Demons")
In 2256, L'Rell preferred to let Voq succeed T'Kuvma, saying she was then free to serve as "your enforcer, defender, campaigner." (DIS: "The Butcher's Knife Cares Not for the Lamb's Cry")
In 2366, defending his choice to accompany Marouk and Brull to Chorgan's ship with security officers, Jean-Luc Picard explained, "For these negotiations to succeed, I must be a mediator, not an enforcer." (TNG: "The Vengeance Factor")