It was four years ago this March 19 that the United States invaded Iraq, triggering massive street protests in San Francisco and a widely criticized military occupation that has become one of the longest in US history. The war has proved to be as bloody and shortsighted as its opponents always claimed it would be. More than 3,100 American soldiers have been killed, as have as many as hundreds of thousands of Iraqis, with little hope of the violence abating anytime soon, despite President George W.Bush's recent deployment of 21,500 more troops. The war has cost the United States about...