Use Brian's open external method.

cms/static/js/base.js

@@ -167,10 +167,15 @@ function linkSmoothScroll(e) {
 }
 
 function linkNewWindow(e) {
-    window.open($(this).attr('href'));
+    window.open($(e.target).attr('href'));
     e.preventDefault();
 }
 
+// On AWS instances, base.js gets wrapped in a separate scope as part of Django static
+// pipelining (note, this doesn't happen on local runtimes). So if we set it on window,
+// when we can access it from other scopes (namely the checklists)
+window.cmsLinkNewWindow = linkNewWindow;
+
 function toggleSections(e) {
     e.preventDefault();
 

cms/static/js/views/checklists_view.js

@@ -6,7 +6,7 @@ CMS.Views.Checklists = Backbone.View.extend({
     events : {
         'click .course-checklist .checklist-title' : "toggleChecklist",
         'click .course-checklist .task input' : "toggleTask",
-        'click a[rel="external"]' : "openInNewTab"
+        'click a[rel="external"]' : window.cmsLinkNewWindow
     },
 
     initialize : function() {
@@ -85,11 +85,5 @@ CMS.Views.Checklists = Backbone.View.extend({
                 },
                 error : CMS.ServerError
             });
-    },
-
-    openInNewTab : function(e) {
-        e.preventDefault();
-        window.open($(e.target).attr('href'));
     }
-
 });