Troll Farms

We study how coordinated disinformation campaigns affect elections. We develop a constrained information design model in which a sender deploys uninformative messages that mimic voters’ exogenous informative signals. Voters initially opposed to the sender’s preferred outcome receive favourable messages, while those in favour are targeted with unfavourable messages to dilute adverse information. The sender’s ability to manipulate political outcomes increases with greater precision of voters’ independent signals, but decreases with polarisation. When messaging is costly, the sender may stop targeting marginally opposing voters while moderating message extremism among supporters.