Ilinois's Democratic senator illuminates the constraints of mainstream politics all too well in this sonorous manifesto. Obama (Dreams from My Father) castigates divisive partisanship (especially the Republican brand) and calls for a centrist politics based on broad American values. His own cautious liberalism is a model: he's skeptical of big government and of Republican tax cuts for the rich and Social Security privatization; he's prochoice, but respectful of prolifers; supportive of religion, but not of imposing it. The policy result is a tepid Clintonism, featuring tax credits for the poor, a host of small-bore programs to address everything from worker retraining to teen pregnancy, and a health-care program that resembles Clinton's Hillary-care proposals. On Iraq, he floats a phased but open-ended troop withdrawal. His triangulated positions can seem conflicted: he supports free trade, while deploring its effects on American workers (he opposed the Central American Free Trade Agreement), in the end hoping halfheartedly that more support for education, science and renewable energy will see the economy through the dilemmas of globalization. Obama writes insightfully, with vivid firsthand observations, about politics and the compromises forced on politicians by fund-raising, interest groups, the media and legislative horse-trading. Alas, his muddled, uninspiring proposals bear the stamp of those compromises. (Oct. 17)