There was a big IMF demo in Washington DC a month or two after September 11... and it was a big letdown, from what I heard and remember. There was just a lot less people. American cops seem to have gotten really emboldened after Sept. 11, so they could repress protests a lot more, like the "freedom of speech cages" at the 2004 RNC. There might have been less media coverage too--when the media have terrorism and wars as their evening bloodsport, they don't need to cover demonstrations as much as they rare in the "peaceful" pre-9/11 world. The timing is definitely there, if not the fault. :]