“Part of the test: will people actually attack LEOs enforcing martial law?”
Not if the US Army is a part of it, and the US Army may be the only institution we have that can hold it together.
I assume, too, that every US soldier has proper PPE and that the US Army has the resources to provide the healthcare for their soldiers.
US military personnel don’t all have PPE, nor do they all have training in how to don and use PPE. Some do - medical and some chemical/biowar defense personnel. Plus many soldiers do have training with chemical warfare gear, but that is not the same as PPE.