"The creation of the United States of America is the central event of the past four hundred years." Thus does Walter A. McDougall of the University of Pennsylvania begin the first volume of his acclaimed new American history, Freedom Just Around the Corner (HarperCollins).Not surprisingly, this central event has evoked a wide range of opinions. Tens of millions of immigrants have voted with their feet to slough off prior allegiances and join the boisterous experiment that makes "life, liberty, and the pursuit of happiness" its official goal.The result has been an astounding success. "We dominate every field of human endeavor...