We asked this very question back in a February 2010 post. In that video, Brennan stated "Those Who Are Anti-Islam are a National Security Threat." It has since been deleted from the web.
Yesterday, a former U.S. Marine and FBI agent confirmed on the trentovision radio/tv show that indeed John Brennan did convert to Islam. Watch to the end. …
Click the "Read More" link to see the video. I personally know John Guandolo to be a highly credible and very knowledgeable on Islam, Muslim Brotherhood, and national Security issues. Please watch this interview. John is on Skype so the video is slightly delayed. Tom Trento does a great job in counter-jihad. Hat tip to CreepingSharia.com