Observing the rise of trade unionism, socialism, and other protest movements during an era of mass society both in Europe and later in North America, elites sought to use imperial jingoism to co-opt the support of part of the industrial working class. The new mass media promoted jingoism in the Spanish–American War (1898), the Second Boer War (1899–1902), and the Boxer Rebellion (1900). The left-wing German historian Hans-Ulrich Wehler has defined social imperialism as "the diversions outwards of internal tensions and forces of change in order to preserve the social and political status quo", and as a "defensive ideology" to counter the "disruptive effects of industrialization on the social and economic structure of Germany". In Wehler's opinion, social imperialism was a device that allowed the German government to distract public attention from domestic problems and preserve the existing social and political order. The dominant elites used social imperialism as the glue to hold together a fractured society and to maintain popular support for the social "status quo". According to Wehler, German colonial policy in the 1880's was the first example of social imperialism in action, and was followed up by the 1897 Tirpitz Plan for expanding the German Navy. In this point of view, groups such as the Colonial Society and the Navy League are seen as instruments for the government to mobilize public support. The demands for annexing most of Europe and Africa in World War I are seen by Wehler as the pinnacle of social imperialism.