Can referendum mechanism be used in deeply polarized societies without invoking existing cleavages? This question is tackled by studying two recent Turkish constitutional referenda, which took place in 2007 and 2010. Turkish society and politics are highly polarized along the secular versus pro-Islam axis. Based on an in-depth study of the campaign materials, media content analysis, and survey data from both cases, it is demonstrated that although both referendum proposals were related to secularism in Turkey, this cleavage was more visible in the 2010 vote. If political parties choose to treat referenda as elections, voters' predispositions are more likely to be reinforced, and partisan voting is more likely to prevail. This research shows that controlled comparisons help in understanding the role of party politics in direct democracy.