when carney dropped the reference, he wasn't helping himself, as the context he was dropping it in was flawed beyond measure. carney then proceeded to repeatedly contradict and make a fool of himself and to this day it's not clear how carney intends to advance what is functionally a world designed around american hegemony without the participation of the united states. carney claims a rupture in the world order, but his policies and behaviour are suggestive of somebody who actually wants more american hegemony and not less of it. canada just wants a return to the preferential treatment it enjoyed since the 60s (or so) and is basically talking out of it's ass to try to get from a to b. however, carney had the basic point that the united states and canada are sibling nations going for him when he made the drop and there is at least some comparison between the athenians and canada and sparta and the united states, even if most liberal americans would cringe rather viciously at this. what the drop really has going for it is that the conflict that the americans fought with the british for control over the anglosphere did have stronger undertones, and it's a memory of that, if a bad one.
i don't think comparing the rise of china to the rise of athens is in any way remotely helpful and if the drop made carney look confused and lost, it is making xi look eager and rash and kind of daft. there is no thucydides trap across the pacific. but carney should take note that running your mouth off without thinking it through fully can have unintended consequences.
however, i have a more appropriate ancient war to drop, and i've dropped it before. the pacific is opening up much as the mediterranean did in the years after alexander. we have an established trading power and an upstart looking to take control. the punic wars are consequently a more accurate comparison for a conflict between china v america, while the peloponnesian war does retain symbolic relevance when discussing conflicts between english-speaking societies.