What would happen in the National Guard if the State Governor and the President gave contradictory orders? https://www.quora.com/What-would-happen-in-the-National-Guard-if-the-State-Governor-and-the-President-gave-contradictory-orders-Please-see-descriptionThere are two different principles at play here. There is a constitutional principle, based on the Supremacy Clause which states (basically) that when state and federal laws conflict, the federal law takes precedence.
The Governor of a state does not simply have the ability to issue orders to guardsmen at his leisure. He/She operates through the military chain of command, which starts at the state's Adjutant General (the senior national guard military officer of the state) and flows both down from there, and upwards through the National Guard Bureau and the operational parent commands of the specific NG unit.
These two underlying principles guide the types of statutory authority by which a commander may give orders to the National Guard.
If the orders that I receive are "Title 10" orders, i.e. they are issued pursuant to statutory authority under Title 10, United States Code (which governs the military), then we have been "federalized" under the reserve component authority of the U.S. military, and the federal authority prevails. This means the full range of federal law applies to us, including the Posse Comitatus act.
If the orders I receive are "Title 32" orders, i.e. they are issued pursuant to Title 32, United States Code (which governs the National Guard specifically), then I am on what's called "Full Time Guard Duty". This means that I am operating under state orders, but whose authority (and funding) are derived from Federal law. That means that once again, Federal law prevails even under Title 32 status. This was never really all that clear, so a few years ago the National Defense Authorization Act (NDAA, the bill that funds the military each year) was amended to explicitly designate certain National Guard commanders as having "dual status", meaning they are explicitly authorized to order guardsmen under both Title 10 and Title 32 status. An important distinction here is that in some cases, guardsmen under Title 32 orders are excepted from the Posse Comitatus act.
There is also purely "state active duty", where the authority, orders, funding, and operational limitations are purely derived from the Governor. The key part being "funding." Because there are no federal funds being offered for state active duty, it is typically used sparingly and for short periods of time.