One major disadvantage of a one-party system is that it negates the freedom of association. This means that citizens are not allowed to freely associate with different political parties or groups that have differing views and opinions. This can stifle democracy by limiting the diversity of ideas and perspectives that can be considered in decision-making processes. Additionally, without the presence of alternative parties, there may be little competition or incentive for the ruling party to improve or be held accountable for their actions, leading to issues with accountability and delayed decision-making.