We shall forbear tracing here the complicated internal history of the I.W.W., that is the friction which immediately arose between the DeLeonites and the other socialists and later on the struggle between the socialists and the syndicalist-minded labor rebels from the West. Suffice it to say that the Western Federation of Miners, which was its very heart and body, convinced of the futility of it all, seceded in 1907. In 1911 it joined the American Federation of Labor and after several hard-fought strikes, notably in Michigan in 1913, it practically became assimilated to the other unions in the American Federation of Labor. The remnant of the I.W.W. split in 1908 into two rival Industrial Workers of the World, with headquarters in Detroit and Chicago, respectively, on the issue of revolutionary political versus non-political or "direct" action. As a rival to the Federation of Labor the I.W.W. never materialized, but on the one hand, as an instrument of resistance by the migratory laborers of the West and, on the other hand, as a prod to the Federation to do its duty to the unorganized and unskilled foreign-speaking workers of the East, the I.W.W. will for long have a part to play. In fact, about 1912, it seemed as though the I.W.W. were about to repeat the performance of the Knights of Labor in the Great Upheaval of 1885-1887. Its clamorous appearance in the industrial East, showing in the strikes by the non-English-speaking workers in the textile mills of Lawrence, Massachusetts, Paterson, New Jersey, and Little Falls, New York, on the one hand, and on the other, the less tangible but no less desperate strikes of casual laborers which occurred from time to time in the West, bore for the observer a marked resemblance to the Great Upheaval. Furthermore, the trained eyes of the leaders of the Federation espied in the Industrial Workers of the World a new rival which would best be met on its own ground by organizing within the Federation the very same elements to which the I.W.W. especially addressed itself. Accordingly, at the convention of 1912, held in Rochester, the problem of organizing the unskilled occupied a place near the head of the list. But after the unsuccessful Paterson textile strikes in 1912 and 1913, the star of the Industrial Workers of the World set as rapidly as it had risen and the organization rapidly retrogressed. At no time did it roll up a membership of more than 60,000 as compared with the maximum membership of 750,000 of the Knights of Labor.