As increasing numbers of employers and governments in industrialized nations hasten to "Americanize" their economic policies, labor laws, and union-avoidance strategies, it has become critical for unions in other countries to learn what they can from the organizing experience of the US labor movement. Most research on factors contributing to US organizing decline has focused on the role played by factors external to the labor movement such as global competition, de-industrialization, changes in workforce demographics, new work systems, deregulation, aggressive employer opposition, and weak and poorly enforced labor laws. US unions, however, have greatly contributed to their own decline by having failed to aggressively organize when they had the power and opportunity in the 1950s and 1960s, and then continuing to fail to commit the resources and strategic initiatives necessary to win in the more hostile organizing climate of the 1970s and 1980s. The author's research over the last 10 years has shown that unions can significantly improve their organizing success, even in the most hostile organizing climate, when they rely on a comprehensive union building strategy. These findings have important implications, not just for the US labor movement, but for unions in other nations as well, as they struggle to regain lost membership and power.