Are you sure? You need to look into the special cases of what happens when one country has high unemployment. There is no guarantee that trade will benefit both countries.
Comparative Advantage says that when two people/parties/countries specialize and trade goods that total wealth is increased. But there is no guarantee that both countries will benefit, especially when one of them has high unemployment.
And that is limited to trading trade goods. WHen one country trades goods for the debt or equities of the other country. It's a wealth drain to the country that lets it happen to them.