Enabler

From SA Mafia Wiki

Enablers are roles that, so long as the player remains alive, some or all of the game's power roles may continue to function. The two most common types are cop-enablers and doc-enablers, which, if alive, allow cops to investigate and doctors to protect respectively.

Typically, an enabler exists for a type of role if there are more than one of them, thus allowing the mafia to fight the multiple cops, for instance, by simply taking out the cop-enabler.