Just look at the UK external dept per capita and you will see what I mean. As long as their investment is a float this debt is not a problem but if not they are in trouble.
Countries like the US and UK have large external debt but also very large external assets to balance it. You can’t ignore one or the other.
Yes that’s why the UK and it’s banks hype up the possibility for the spanish sector to recover since they are in so deeply invested in their economy. If Spain continues or worse on this route it will mean a ten fold multiplying effect on Ireland and the UK. Their assets will be shown not to be worth close to what they are now on paper. These bad investments will be handed over to the tax payer via the normal national debt eventually when it goes sour.
The effect on the US is harder to predict.