It is on Python 2.7a2

>>> os.popen('"C:\\Python27\\python.exe" -c "import sys; print sys.argv" 42').read()
''

>>> os.popen('""C:\\Python27\\python.exe" -c "import sys; print sys.argv" 42"').read()
"['-c', '42']\n"

>>> os.popen3('"C:\\Python27\\python.exe" -c "import sys; print sys.argv" 42')[2].read()
'\'C:\\Python27\\python.exe" -c "import\' est pas reconnu en tant que commande interne ou externe, un programme executable ou un fichier de commandes.\n'

It may be related to the test_popen failure.
Actually, it seems that the outer double quotes are removed before executing the cmdstring:
  C:\Python27\python.exe" -c "import
 ^                                  ^