The latest call for national guard assistance was not met by Delaware's Commander-In-Chief - Governor John Carney.
Mary McManamon, a professor of law at Delaware Law School for Widener University, cited the means that a president can summon the aid of state troops:
"There are two routes for a president to enlist the help of a state National Guard. By way of Title 10, which governs the armed services. When the president does that, the Commander-In-Chief shifts from being the governor to being the president," said McManamon. "The other route is through Title 32. In that case, the Commander-In-Chief remains the governor of the state and that's what President Trump has used. So under those circumstances, the governor can refuse to allow the troops to go."
If President Trump really wanted to press the issue, there's only one way around a refusal of a Title 32 request denial.
"The only way for the president to overrule it would be to call up Title 10," said McManamon.