Now, there’s two way to read this comic. the intended way, or the true-to-reality way.
The intended way is that the PIIGS crisis is because of “DEBT!”, and that’s the way the US is headed.
The true to reality way is that the cause of the crisis that first built up a huge economic bubble that burst is the same Free Market ideology the US has been pushing since Reagan. Smaller economies are more vulnerable to the effects, partly also because the US still has (comparatively) lots of traditonal industry and fall-back subsidised economy. The best barometer for this is ICeland, since they took neo-liberal free market capitalism furthest, and they are also a country with limited, if nonexistent natural resources and conventional industry. Iceland crashed first, and the only reason it didn’t go to hell is that it’s an island nation far from everything, and they had to sort their shit out by themselves.