I don't think the author meant that seriously. You see the quote around "barbarian tribes"? I think he considered this notion sarcastically, as this is "barbarian tribes" is often used by people less knowledgeble abou the topic.

And for the US to implode within a few weeks, there must have been considerable rot inside. I am really not sure where precisely it started, but I consider Bretton Woods (both the system and it's breakdown), Nixon with the final breakdown of honor in politics, Reagan and his "trickle-down economy" lie Reageanomics, and Bush Junior with his Gulf War key milestones in that process. Notice a trend? They were all Republicans. That Trump puts the final nail into the US' coffin is only consequential.