As evidenced by the 2016 US presidential election, conspiracy theories such as birtherism, the belief that Barack Obama is not a natural-born citizen, have become more impactful on modern-day liberal democracies. This study investigates the consequences of the conspiratorial narratives espoused by populist candidates, arguing that the creation of a narrative involving a “conspiring” establishment figure can positively benefit populist candidates during elections by allowing them to position themselves as defenders of “the people”. Taking the case of Donald Trump and the birther conspiracy theory, empirical testing indicates that by helping to spread birtherism, Donald Trump was able to create for himself a core group of supporters who turned out to vote for him in both the Republican primaries and general election. Moreover, when tests are performed to investigate whether this was a consequence of rallying a right-wing base or mainstreaming the fringe conspiracy theory, significant positive relationships are demonstrated not with more conservative birthers, but instead with the more moderate ones, testifying to the strength of the mainstreaming effect.
