Index: Lib/email/header.py
===================================================================
--- Lib/email/header.py	(Revision 55339)
+++ Lib/email/header.py	(Arbeitskopie)
@@ -78,8 +78,11 @@
             continue
         parts = ecre.split(line)
         while parts:
-            unenc = parts.pop(0).strip()
-            if unenc:
+            unenc = parts.pop(0)
+            # whitespace is ignored between encoded-words
+            if decoded and decoded[-1][1] is not None and unenc.isspace():
+                pass
+            elif unenc:
                 # Should we continue a long line?
                 if decoded and decoded[-1][1] is None:
                     decoded[-1] = (decoded[-1][0] + SPACE + unenc, None)