I’ve had a vague sense of late that there’s a connection between the weak dollar, on the one hand, and rising asset prices, on the other. But I took some comfort in that: prices aren’t really going up as much as they look, it’s just that the dollar’s going down, so everything looks good in dollar terms.

Now, along comes Nouriel Roubini to burst my bubble. This isn’t a case of the weak dollar making asset prices look good; in fact, it’s the “mother of all carry trades”, setting up “the biggest co-ordinated asset bust ever”.

I believe him.

Nouriel’s analysis is quite compelling, given the way the carry trade works. In its most harmless form, people borrow at low rates in a funding currency and then...