I wouldn't be surprised if North America splintered into a warlord era after the fall of American Capitalism.

This one's probably not going to happen. I would assume the fracture of the power of the American state would allow for a power vacuum to form. I would further assume certain polarized demographic bubbles in the US wouldn't feel confident allowing the legal government of the United States to govern them.

From these assumptions, I think it's possible but unlikely that North America will see a rise of warlords. Perhaps this could be like China's warlord era, or perhaps it would be unlike anything anyone's seen before - who knows? Regardless, I'll reiterate, probably not going to happen.