Civil society actors collectively organized online and offline to nominate themselves and oppose the Vietnamese Communist Party in the 2016 legislative election. The level of opposition coordination among these independent self-nominees exceeded and qualitatively differed from previous atomized attempts in the 2011 election. External shifts in the political opportunity structure offer only a partial explanation for the increased coordination among independent candidates in Vietnam's 2016 self-nomination movement. In this article, I theorize that it is the combination of both opportunity structure and overlapping linkages across spheres of social contention and civil society, all accumulated from a prior history of protests and activism, that provide the conditions for the emergence of independent self-nominees and opposition coordination in single-party-elections. In Vietnam, a cumulative process of participation in social contention and civil society organizations during 2011 to 2016 allowed actors to develop linkages that strengthened their repertoires of contention and resonant frames of collective action. These linkages, combined with favorable political opportunities, effectively facilitated greater mobilization and coordination among independent self-nominees in the 2016 election.