  Political organizations worldwide keep innovating their use of social media
technologies. Here, we document a novel configuration of technologies and
organizational forms used to manipulate Twitter trends in the 2019 Indian
general election. The organizers rely on an extensive network of WhatsApp
groups to coordinate mass-postings by loosely affiliated political supporters.
To investigate the campaigns, we joined more than 600 political WhatsApp groups
that support the Bharatiya Janata Party, the right-wing party that won the
general election. We found direct evidence of 75 hashtag manipulation
campaigns, including mobilization messages and lists of pre-written tweets. We
estimate the campaigns' size and whether they succeeded in creating controlled
social media narratives. We show that the campaigns are smaller than what media
reports suggest; still, they reliably produce Twitter trends drawing on the
voices of loosely affiliated supporters. Centrally controlled but voluntary in
participation, this novel configuration of a campaign complicates the debates
over the legitimate use of digital tools for political participation. It may
have provided a blueprint for participatory media manipulation by a party with
popular support.
