The decades of the 1870s and the 1880s were marked by economic and social turmoil, including the Long Depression of 1873–1879, a series of recessions during the 1880s, the rise of organized labor and strikes, and the 1886 Haymarket affair and its controversial aftermath. Moreover, American capitalism's tendency towards concentration into ever larger and less competitive forms—monopolies, oligopolies, and trusts—began to make itself evident, while emigration from Europe expanded the labor pool and caused wages to stagnate. The time was ripe for new ideas about economic development which might ameliorate the current social disorder.