>>8797836 (lb)
Regarding presidential authority vs. authority of governors during a declared emergency/disaster
"The President may ... coordinate all disaster relief assistance ... provided by Federal agencies, private organizations, and State and local governments, including precautionary evacuations and recovery." 42 U.S.C. s. 5170a(2) (Stafford Act).
My read of this is that, in an EMERGENCY (which there is), the President may commandeer the "recovery" efforts of state and local governments -- that is, the President MAY call the shots at his discretion.
Stafford Act is probably constitutional under Art. I, s. 8: "The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States."