This paper documents how democratization in South Korea, Taiwan, and Hong Kong since the 1980s has led to the materialization of growing political cleavages. Political integration, manifested by attitudes towards North Korea in South Korea, and towards mainland China in Hong Kong and Taiwan, have been a key issue structuring party competition and electoral behaviors in the three territories. In Hong Kong and South Korea, this issue has sharply divided old and new generations, albeit in a somewhat different way. In Hong Kong, younger cohorts are substantially more likely to vote for parties supporting lower political integration. In South Korea, older generations show significantly higher support for unification, but they are also much more likely to vote for conservatives, who firmly oppose any attempt to engage with the North Korean regime, a phenomenon rooted in decades of tensions and fiercely anticommunist regimes. In Taiwan, such a strong generational divide is absent, but the independence/unification cleavage has interacted with ethnicity: immigrants from mainland China and their descendants have been more supportive of the pro-unification Kuomintang than natives. This is also the case in Hong Kong, where sustained immigration from the mainland has come with the emergence of a strong anti-immigration cleavage. We argue that the strength of these cleavages and the lack of political mobilization of the working class for historical reasons have played a key role in explaining the near absence of class cleavages in all three territories. While economic concerns do play a role in nurturing mass mobilizations, cultural and political identities, rather than material concerns, seem to continue shaping party systems in East Asia.