America's Missouri River may be the nation's longest and most historically significant river, encompassing many of America's natural wonders between Missouri and Montana, draining almost 600,000 square miles in ten states and part of Canada, and, after Lewis and Clark's expedition 200 years ago, opening the West to a frenzied rush of expansion. But the Missouri is also the site of a vast, politically driven drama. It tops a list of emerging big-stakes...