What I mean is unbridled self-enrichment, corruption, greed, hubris and hedonism (in the negative, not the philosophical sense) of the elites of a given empire, which often had a certain share in the decline of formerly effective administrative and economic structures, legal systems etc. The excessive abuse of power by the powerful for selfish purposes. For a long time the ancient Romans were very aware of the creeping danger that came with considerable power in the hands of just a few. For example the expression “memento mori” (remember that you will die) likely comes from this context: The Romans used to say that to generals when they returned from a successful campaign as to remind them that they are not almighty gods but just mortals like everyone else. The late Roman elite however seems to have forgotten this as they became more greedy and selfish instead of being somewhat humble servants of their empire - they became decadent. But yes, if anything, that was of course just one factor among many in the decline of former empires. My point is just that even today, the excessive greed of a few very powerful people threatens not only their own power base, but even the survival of humanity as a whole. I simply think that we need to change fundamentally and urgently if we want to mitigate the foreseeable consequences of climate change to some extent - Trump is not going to do that at all.