* American political life has been marked by family dynasties, which generally rise, coast and fall, leaving broken ambitions in their wake. So argues journalist and biographer Emery (Washington) in this study of such American political families as the Adamses, the Roosevelts, the Kennedys and the Bushes. While Emery examines the ascents of Theodore Roosevelt and John F. Kennedy, her real focus is on the frustrations and tragedies that, like the embarrassing relatives the families try to shield from public view, have long attached themselves to these dynasties. Emery predictably proposes that the younger generations chafe against unachievable expectations and express their anger in the wayward behavior she describes as a dynastic curse. Thus the dissolute, alcoholic sons of John Adams find modern parallels in the post-1968 Kennedys and the preconversion George W. Bush, all of whom lost their way in their ancestors' long shadows. However, Emery's analysis fails to rise above the simplistic. Emery also revels in the vexations of Al Gore for a full three chapters—two more than she gives to the entire Roosevelt saga. There is much to be said about political dynasties in the United States, but this is hardly the first word, let alone the last. (Dec.) (Publishers Weekly, October 16, 2006)