diff --git a/lib/Trait.js b/lib/Trait.js
index dc0758e..878cdfe 100644
--- a/lib/Trait.js
+++ b/lib/Trait.js
@@ -947,10 +947,16 @@ function tctor( tc, base, privsym )
         // (but not private); in return, we will use its own protected
         // visibility object to gain access to its protected members...quite
         // the intimate relationship
-        this[ f ] = C( base, this[ privsym ].vis )[ privsym ].vis;
+        var tinst = C( base, this[ privsym ].vis );
+        this[ f ] = tinst[ privsym ].vis;
 
         // TODO: this should use util.defineSecureProp
-        this[ f ].__inst = this[ privsym ].inst;
+        // we set __inst on the trait object itself (public visibility
+        // object, which is okay, since the trait is encapsulated anyway)
+        // because otherwise, in the case of an ES3 fallback, `vis' will be
+        // affected by __inst defined on `base', leading to a fight over
+        // ownership that I spent too much time trying to figure out
+        tinst.__inst = this[ privsym ].inst;
 
         // rebind trait's supertype context (if any) to our own, causing us
         // to share state