This article reflects on the inclusion-moderation thesis, which asserts that parties from the radical right become like mainstream parties once they move from the opposition to government. This mainstreaming primarily occurs through the moderation of issue positions and the decline of populism. In this article, I focus on populism and consider the role of party leadership for government parties. I distinguish between traditional and managerial leadership. While traditional leadership employs an adversarial strategy toward mainstream parties, managerial leadership adopts an accommodative strategy. This article looks at three phases: 1) the opposition period; 2) in office under traditional party leadership; 3) in office under managerial party leadership. I expect that, compared to the second phase when the party is in office under traditional party leadership, levels of populism are higher during the opposition period and lower when it is in office under managerial party leadership. The empirical part of this article conducts a quantitative content analysis on the populist communication of the Geneva Citizens’ Movement, a radical right party from Switzerland. The findings tend to support my theoretical argument.