If US National Guard Troops are being sent to Africa, by whose authority? Do not State Governors have to give permission, and for what reason is this being done?

Is it a "test case" to see if they can get away with it as a prerequisite for vastly more of the same Nationwide ... maybe to reduce the number of troops @ home that might otherwise seek to protect the common citizen here when our governments decide (probably soon) to pull a "Trudeau" on us ?