Each year about 60 million people flee their home country and seek to cross into developed countries, thus urging the latter to develop different policy responses to face the growing concerns about how immigration may affect social order. We design a novel two-part public goods experiment with radical income asymmetry between groups to investigate how voting on (not) helping less-endowed others affects pro-social behavior in the voting groups. We find that no group ever votes to help less-endowed ones. This, in turn, results in a breakdown of prosociality within the voting groups. We study the reasons why the implementation of voting—compared to no voting or to imposed solidarity—results in a significant, negative impact on cooperation levels within the voting groups.