In answering the question — Why was the direct primary introduced by so many states between 1899 and 1915? — it is important to distinguish between several different aspects of the answer.
The first has to do with long-term pressure from within the parties for reform of the caucus-convention system in selecting candidates. The informal practices of that system, which had worked reasonably well at the height of the Jacksonian democracy, were performing much less well with population expansion and urbanization. With the decreased effectiveness of older methods of control, parties found themselves now using nomination practices that brought them into disrepute and which made it more difficult to coordinate intraparty activities. However, any proposed reform of the system would be constrained in two ways. On the one hand, the decentralization of the parties meant that reforming them by creating party rules would never be sufficient, because parties at the state level (and below) would be unable to provide enforcement. That is why it became necessary to use state law to effect reform; the many statutes that were enacted in the 1890s are not evidence of the parties being “punished” by antiparty reformers, but, rather, that institutionalization was possible only through mechanisms external to the parties. On the other hand, any reform had to be compatible with the Jacksonian ethos that parties were the means of effecting democracy, and any redesign of them had to be directed toward maximizing participation within them. Arguably, one of the reasons that in the twentieth century American parties ended up by being much weaker than their European counterparts was that so much had been expected of them during the nineteenth century. The persistence of a belief that parties should be vehicles for mass participation precluded any reforms that might have reduced participation in the nominating process, and correspondingly advantaged any schemes that were likely to increase it.
The second aspect concerns change in the 1890s. There were two developments in that decade that were to further limit the direction that reform