heres a quote on it
In theory and usual practice, the Governor of the State. He or She ( some states have had female governors- like New Jersey under Whitman) can call out the National Guard to control civil emergencies such as riots, etc. However, as the President of the United States has CINCUS ( Commander In Chief- US) he can and does have the authority to federalize NG units which are technically a part of the US Army and dispatch them on various missions- one peacetime example was the Federalization of guardsmen to contain racial problems in Little Rock, Arkansas during the Desegregation battles. This is the best known action of the type- unlike deployment of Guard units to foreign wars- for example stop-loss assignments in Iraq
so in fact the if the governor activated the national guard biden could federalize them and then he would be commander and chief and his power would supersede the governors. So the governor of tx would be on shaky ground activating them. Biden could take control and if the governor tried to interfere it could be construed as treason. It could backfire on him if he tried. Especially with the democrats having the house and senate. So we really cant blame Abbot for being intelligent enough to know it would backfire.