But one popular theory is the accumulated effect of corruption of the leaders - people who saw being in leadership as a way to enrich themselves by taking actions in their own personal interest and against the interest of the empire. I think about this idea a lot. I'm not making a huge statement like "the American empire is falling", but I am saying that we see a lot of corruption in the USA. As an "Americanophile" western european, I also find it shocking.
[1] https://en.wikipedia.org/wiki/Fall_of_the_Western_Roman_Empi...
His actual approval ratings are down, but there are still tens of millions of people who will vote to support his agenda this November. Many of those votes will come from people who say they disapprove, but are disapprove of his opponents even more strongly.
If I'm right about that, it's an even harder problem than the Romans had. In a lot of ways, the "fall" of Rome wasn't that big a deal. Many people's lives didn't change at all. Americans want this rot of their own empire.
Good emperors were able to salvage Rome, even relatively late in the empire. I don't know if an Aurelian could do much to help us at this point, even if we found one.