The dollar has been in danger of collapse (according to the financial press) almost constantly since I started following currency markets in the mid-1980s. A great many influential academics and journalists have been telling us for 20 years that the dollar's role as a world reserve currency was at an end, and that we should expect a free-fall. I'll believe it when I see it.

The current weakness can be explained the old-fashioned way: US investment yields (especially bonds) vs. those in other countries. If the weakness continued when the fundamentals are more favorable, that will be interesting.