The Federal Emergency Management Agency - a former independent agency that became part of the new Department of Homeland Security in March 2003 - is tasked with responding to, planning for, recovering from and mitigating against disasters.

In 2001, President George W. Bush appointed Joe M. Allbaugh as the director of FEMA. Within months, the terrorist attacks of Sept. 11th focused the agency on issues of national preparedness and homeland security, and tested the agency in unprecedented ways. The agency coordinated its activities with the newly formed Office of Homeland Security, and FEMA's Office of National Preparedness was given responsibility for helping to ensure that the nation's first responders were trained and equipped to deal with weapons of mass destruction.

Billions of dollars of new funding were directed to FEMA to help communities face the threat of terrorism. Just a few years past its 20th anniversary, FEMA was actively directing its "all-hazards" approach to disasters toward homeland security issues.

The above is taken from the 'History' section of the Official FEMA web site.

FEMA's origins go back as far as 1803. Subsequent to becoming part of the Department of Homeland Security it would appear that funding, resources and training were allocated to expand the role and capabilities of FEMA with regard to "security issues" As both Katrina and Rita were natural disasters, FEMA's procedures and mode of operation for such circumstances would apply, there was no terrorist threat, there were no 'security isues' so revamped procedures to address those circumstances would not automatically come into play. What would, was the Federal support role to State Authorities, and as GUEST pointed out, if state had not requested assistance before Katrina struck, they proved extremely difficult to contact after. The rescue folks from Vancouver, where not hindered in this same way.

Everyone thought that plans were in place, they were. Everyone thought that those plans were adequate, that proved to be incorrect, as the plan relied on there being some organisation/civil administration in place and functioning to liaise and co-ordinate with. In the case of Katrina there wasn't. Run on just a couple of weeks and Rita arrives, by this stage plans have been altered, the response was different, the storm did not impact a major centre of population and its affects were lessened. Learning by experience is what mankind has always had to do.