Forbes blames the latest slide on a slowing housing market. Our dollar is pretty much never as strong as the pound. The Brits opted out of the Euro because they knew full well that they would basically loose money by tying their economy to the EU. Upset a few of the other countries that were hoping to bolster their currency by associating with England. Also, there's countries like China that are heavily invested in the American dollar that have been gradually liquidating there American assests, oh yeah, and let's not forget our enormous (record) debt.