diff --git a/traits/adaptation/adaptation_manager.py b/traits/adaptation/adaptation_manager.py
index f093a0550..f6d2a0adf 100644
--- a/traits/adaptation/adaptation_manager.py
+++ b/traits/adaptation/adaptation_manager.py
@@ -92,10 +92,7 @@ def provides_protocol(type_, protocol):
           True if the object provides the protocol, otherwise False.
 
         """
-
-        # We do the 'is' check first as a performance improvement to save us
-        # a call to 'issubclass'.
-        return type_ is protocol or issubclass(type_, protocol)
+        return issubclass(type_, protocol)
 
     #### 'AdaptationManager' protocol ##########################################