Trump has more energy than a dozen men his age
Trump's supporters are strong, clear thinking, God fearing patriots who care for their fellow citizens, want their Federal government ready and able to assist in times of severe weather, want to end child trafficking, want a country free of fentanyl and hard drugs, want a country of law and order, not open borders, want to compete with the world on a level playing field and want to be left alone to enjoy life, liberty and pursue happiness. And yes, free to bear any arms they desire. They also want to live in peace and worship God as they wish.
Some natural disasters are too big for a single state. Some are multi-state and require coordination and logistics beyond the capability of each state separately. Defense of the nation could also be appropriately applied as defense against natural disasters.