Lol, paypal's short message is longer than the long message.

lolpaypal.txt

DoExpressCheckoutPayment failed:
{
  'ACK': 'Failure',
  'TIMESTAMP': '2013-11-26T03:18:22Z',
  'L_SEVERITYCODE0': 'Error',
  'L_SHORTMESSAGE0': 'Transaction refused because of an invalid argument. See additional error messages for details.',
  'L_LONGMESSAGE0': 'A successful transaction has already been completed for this token.',
  ...
}