In 1898, the American Federation of Labor feared that colonial expansion would militarize the republic and undermine the living standards of American workers. Subsequent expansion of industrial production and of trade union membership soon replaced the fear of imperial expansion with an eagerness to enlarge the domain of American unions internationally alongside that of American business. In both Puerto Rico and Canada important groups of workers joined AFL unions on their own initiative. In Mexico, where major U.S. investments shaped the economy, anarcho-syndicalists enjoyed strong support on both sides of the border, and the path to union growth was opened by revolution. Consequently the AFL forged links there with a labor movement very different from itself. Unions in Mexico became tightly linked to their new government, while World War I drove the AFL's leaders into close collaboration with their own. The Pan-American Federation of Labor was more a product of diplomatic maneuvering than of class solidarity.