Blockchain governance is paramount to leading securely a large group of users towards the same goal without disputes about the legitimacy of a blockchain instance over another. As of today, there is no efficient way of protecting this governance against an oligarchy. This paper aims to offer a new dimension to the security of blockchains by defining the Swift Proportional Governance problem. This problem is to rapidly elect governance users that proportionally represent voters without the risk of dictatorship. We then design and implement an open permissioned blockchain called SocChain (Social Choice Blockchain) that mitigates bribery by building upon results in social choice theory. We deploy SocChain and evaluate our new multi-winner election DApp running on top of it. Our results indicate that using our DApp, 150 voters can elect a proportionally representative committee of 150 members within 5 minutes. Hence we show that SocChain can elect as many representatives as members in various global organizations.