From Bespoke Investment Group:
...Falls in the Dollar are coinciding with gains in equity markets and economic stability worldwide, since the US currency is now being treated as a safe haven. Go figure....MORE
If you go to Bespoke, they have a table showing the second largest daily decline in the buck came the day after the 1985 Plaza Accord, with declines #3 and 4 coming earlier in that year.
The Plaza Accord was a deliberate decision to depreciate the dollar, with #3 and 4 being a kind of early warning of the plan. We had a strong stock market for the next two years.
In February '87, the Louvre Accord was signed, to halt the decline of the dollar. This was one of the backdrops for the crash of '87. It didn't precipitate the market downturn that began six months, almost to the day, later but there is a correlation.
Correlation is not causation but the end of a dollar decline in July of 2008 got me thinking of these things. I'm guessing we will return to this idea, in the meantime watch the (formerly) almighty buck.