"Despite the fact that the 1927 flood left 1 percent of the U.S. population homeless, had an estimated death toll in the thousands, and burdened the Red Cross with nearly 700,000 refugees to feed, there was great reluctance on the part of Southern leaders to initiate federal action. When President Calvin Coolidge refused to call Congress into session to respond to the flood, they backed him."
The feds did help and it did set a precedent for reconstruction, but it was not for the feds to be first responders.