diff -r 0b78a8c35357 Lib/smtplib.py
--- a/Lib/smtplib.py	Thu Dec 15 18:58:35 2016 -0500
+++ b/Lib/smtplib.py	Fri Dec 16 15:04:13 2016 -0500
@@ -913,20 +913,21 @@
         # Section 3.6.6). In such a case, we use the 'Resent-*' fields.  However,
         # if there is more than one 'Resent-' block there's no way to
         # unambiguously determine which one is the most recent in all cases,
-        # so rather than guess we raise a ValueError in that case.
+        # so rather than guess we raise a ValueError in that case.  See RFC 5322
+        # section 3.6.6, first paragraph for more details about the "should" that
+        # the code should respect.
         #
         # TODO implement heuristics to guess the correct Resent-* block with an
         # option allowing the user to enable the heuristics.  (It should be
         # possible to guess correctly almost all of the time.)
 
-        self.ehlo_or_helo_if_needed()
-        resent = msg.get_all('Resent-Date')
-        if resent is None:
-            header_prefix = ''
-        elif len(resent) == 1:
-            header_prefix = 'Resent-'
-        else:
-            raise ValueError("message has more than one 'Resent-' header block")
+        #Resent or original?
+        header_prefix = 'Resent-' if len(msg.get('Resent-Date','')) >= 1 else ''
+        
+        # RFC 5322 section 3.6, 4th Paragraph
+        if msg.get('Date',None) is None:
+            msg['Date'] = email.utils.formatdate()
+
         if from_addr is None:
             # Prefer the sender field per RFC 2822:3.6.2.
             from_addr = (msg[header_prefix + 'Sender']
@@ -1110,5 +1111,6 @@
 
     server = SMTP('localhost')
     server.set_debuglevel(1)
-    server.sendmail(fromaddr, toaddrs, msg)
+    #server.sendmail(fromaddr, toaddrs, msg)
+    server.send_message(from_addr=fromaddr, to_addrs=toaddrs, msg=email.message_from_string(msg))
     server.quit()
diff -r 0b78a8c35357 Lib/test/test_smtplib.py
--- a/Lib/test/test_smtplib.py	Thu Dec 15 18:58:35 2016 -0500
+++ b/Lib/test/test_smtplib.py	Fri Dec 16 15:04:13 2016 -0500
@@ -531,13 +531,14 @@
                                  re.MULTILINE)
             self.assertRegex(debugout, to_addr)
 
-    def testSendMessageMultipleResentRaises(self):
+    def testSendMessageMultipleResent(self):
+        first_date = 'Thu, 1 Jan 1970 17:42:00 +0000'
         m = email.mime.text.MIMEText('A test message')
         m['From'] = 'foo@bar.com'
         m['To'] = 'John'
         m['CC'] = 'Sally, Fred'
         m['Bcc'] = 'John Root <root@localhost>, "Dinsdale" <warped@silly.walks.com>'
-        m['Resent-Date'] = 'Thu, 1 Jan 1970 17:42:00 +0000'
+        m['Resent-Date'] = first_date
         m['Resent-From'] = 'holy@grail.net'
         m['Resent-To'] = 'Martha <my_mom@great.cooker.com>, Jeff'
         m['Resent-Bcc'] = 'doe@losthope.net'
@@ -545,8 +546,13 @@
         m['Resent-To'] = 'holy@grail.net'
         m['Resent-From'] = 'Martha <my_mom@great.cooker.com>, Jeff'
         smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
-        with self.assertRaises(ValueError):
-            smtp.send_message(m)
+        smtp.send_message(m) #validate that no errors are raised
+        self.assertEqual(first=m.get('Resent-Date'),
+                         second=first_date,
+                         msg="""
+                             The Resent-Date order is not read correctly or
+                             something wrong happened.
+                             """)
         smtp.close()
 
 class NonConnectingTests(unittest.TestCase):