Illiberal regimes use overt and covert political communication to influence public opinion in democracies. We present an argument about how such propaganda impacts targeted publics. We posit that effectiveness depends on whether the source of the message is revealed, on the nature of the issue, and on individual characteristics of the recipients. We test these propositions in Germany, in the context of Kremlin messaging, using eight survey experiments administered to a large sample of German voters (n = 2, 303). Citizens who mistrust the government, believe in conspiracy theories, or are generally disconnected from politics are vulnerable to propaganda warfare that involves anti-mainstream messaging, while the rest of the populace is not. At the same time, providing a pro-Western, mainstream viewpoint and outing the Russian source are not generally effective countermeasures. We discuss the implications of illiberal regime communication for information wars between states and for the internal workings of democratic politics.
