diff --git a/src/main/java/org/scribe/model/OAuthRequest.java b/src/main/java/org/scribe/model/OAuthRequest.java
index ec7f02308..69aeb75d4 100644
--- a/src/main/java/org/scribe/model/OAuthRequest.java
+++ b/src/main/java/org/scribe/model/OAuthRequest.java
@@ -41,12 +41,12 @@ public void addOAuthParameter(String key, String value)
 
   private String checkKey(String key)
   {
-    if (!key.startsWith(OAUTH_PREFIX) || !key.equals(OAuthConstants.SCOPE))
+    if (key.startsWith(OAUTH_PREFIX) || key.equals(OAuthConstants.SCOPE))
     {
-      throw new IllegalArgumentException(String.format("OAuth parameters must either be %s or start with '%s'", OAuthConstants.SCOPE, OAUTH_PREFIX));
+      return key;
     } else
     {
-      return key;
+      throw new IllegalArgumentException(String.format("OAuth parameters must either be %s or start with '%s'", OAuthConstants.SCOPE, OAUTH_PREFIX));
     }
   }