And he will do what about it exactly?
Send in the US Marshall's to arrest Northam. USC Title 18 Section 242. Deprivation of Rights under color of Law.
It's a Federal felony that can carry up to the death penalty.
Or is that not enough?
He can act to uphold and defend the constitution. There fore if the state Legislature acts to deny our constitutional rights, he can intervene militarily until the judges and the congress sort it all out. He can declare the Virginia legislature and governor as committing insurrection against the constitution and basically create a military district out of the state and have those who are trying to take away our rights arrested.