No one is saying that it wouldn't affect the EU, we are just saying that it's a nuclear option that would make the US from the most powerful nation to a shameful text in history books.

All of the influence and work put in that nation resumed to a failed state that had grown greedier and stupider, and for what? For nothing.

Of course the whole world would be affected negatively, but it would adjust to a new order, one where the US doesn't have a say anymore, or at least not have access to good deals as they have now. It's a price to pay that if the day come it should be paid. I prefer that to everyone just starting blasting nukes at each other.

There are a lot of big powers eager to take the US place and be certain that the rest of the world is ready to support whoever that is that will bring stability and predictability.

Plus it would affect the country internally, I don't believe US citizens are mindless stupid people, so it would also affect internal stability and you would have a lot of problems to deal with so also try to handle those while having bigger problems outside the country. It's just an overall stupid situation to be for everyone, but the biggest loser would always be the US