Big drop last week.

Can someone please explain the political reasons for this drop? How does the Canadian economy compare to the US economy in terms of the mortgage crisis and bank debt?

From Bloomburg:

As commodity prices continue to fall and political uncertainty rises we have become increasingly cautious on the Canadian dollar,'' wrote Shyam Devani, Todd Elmer, Tom Fitzpatrick, Michael Hart and Mike Rosborough at Citigroup Global Markets Inc.

Thanks in advance

BK