It is easy to believe that the security threats are exaggerated and complacency can set in. The truth is that there are small networks of sympathizers to radical Islamist causes in Kenya and also apparently in Tanzania. It was only a matter of time before a high profile target such as Westgate was attacked. For some years Nairobi's Kenyatta International Airport has been regarded by Western intelligence agencies as particularly vulnerable, and international airlines have invested in additional security screening procedures that seem to have reduced the risk.