The entire south america is pissed off for example, and I've seen people here talking about trying to convince europeans to join us in a anti-US war, WWII style (ie: demonize the US and throw the entire world against it).
And it might work, plainly because US policies since WWII mostly pissed everyone off, almost all countries have reasons to want to see US destroyed, and I am pretty sure that with enough incentive, you might end with the entire world attacking the US...
Other possible scenarios are EU civil war, South America vs EU war, or Asian countries starting their own already incoming wars during this chaos, hoping to drag one western country or another to their side.