"FEMA was used once before, under President Reagan, for counter-terrorism and as a result, natural disaster response and mitigation suffered. It was repaired under President Clinton, but again, counter-terrorism has eaten up FEMA's natural disaster budget and skills. This document includes a review of FEMA's history, and offer some possible explanations for its failures in 2005."
Homeland Security Affairs Journal: http://www.hsaj.org/hsa/
Homeland Security Affairs (2005), v.1 no.2, article 4