diff --git a/gtsam/nonlinear/NonlinearFactor.h b/gtsam/nonlinear/NonlinearFactor.h
index a5f06a090..85d13585a 100644
--- a/gtsam/nonlinear/NonlinearFactor.h
+++ b/gtsam/nonlinear/NonlinearFactor.h
@@ -525,7 +525,7 @@ namespace gtsam {
       if(var1 < var2 && var2 < var3)
         return IndexFactor::shared_ptr(new IndexFactor(ordering[key1_], ordering[key2_], ordering[key3_]));
       else if(var2 < var1 && var1 < var3)
-        return IndexFactor::shared_ptr(new IndexFactor(ordering[key2_], ordering[key2_], ordering[key3_]));
+        return IndexFactor::shared_ptr(new IndexFactor(ordering[key2_], ordering[key1_], ordering[key3_]));
       else if(var1 < var3 && var3 < var2)
         return IndexFactor::shared_ptr(new IndexFactor(ordering[key1_], ordering[key3_], ordering[key2_]));
       else if(var2 < var3 && var3 < var1)