Shaun Bowler and Todd Donovan, "Direct Democracy and Political Parties in America," Party Politics, 12 (September, 2006), 649-669.

First Paragraph:
American Populists and their allies who fought to establish direct democracy in American states promoted the initiative device as a means to alter rules governing political parties (Barnett, 1915; Burnham, 1970; Piott, 2004). After direct democracy was adopted in 17 American states between 1898 and 1912, the popular initiative was used in attempts to strip state legislators of their power to appoint US Senators, and to remove control of nominations from party organizations via introduction of the direct primary. During this period, direct democracy was also used in attempts to establish procedures for recall of elected officials, to amend election laws, redistrict, establish civil services, establish corrupt practices acts, and eliminate straight party ballots (Piott, 2004: appendix)

Figures and Tables:
Table 1. Populist influence on state adoption of initiative process
Table 2. Probability of state adopting initiative process, predicted by Populist electoral support in a state
Table 3. Estimates of characteristics of states' initiative process, predicted by years since Populist era that state adopted
Table 4. Political reforms adopted by initiative in US states (selective examples)
Table 5. Influence of initiatives on twentieth-century state party organizations. Estimates of strength of state party organizations
Table 6. Influence of initiatives on twentieth-century state legal environment for parties. Estimates of amount of regulation on state parties

First Paragraph of Conclusion:
Although these examples suggest an active party presence in American direct democracy, the role of parties in direct democracy in the United States still remains quite different from the relationship between parties and direct democracy in much of Europe. In Europe, referendum campaigns may be understood in light of the fact that the referendum will decide major national policy questions, and/or be seen as a referendum on a proposal put forward by governing parties. American parties have much less control over which measures reach the ballot, and American parties still find themselves on occasion fighting proposals that are inconsistent with a responsible party model of representative democracy. At the same time, however, they may also use the initiative to take advantage of popular policy proposals that may mobilize certain groups of voters and thus advance the interests of their candidates.