There is a mistaken idea that political individualism is in conflict with the common good.
I think the first part of the disagreement I have with non-individualists is in defining just what the common good consists of.
To “promote the general Welfare,” as the Preamble to the Constitution of the United States calls for, it is not sufficient to promote just anyone’s welfare, but the welfare common to everyone. The common good (properly understood) would be a good common to all people. What individualists recognize is that a flourishing society will consist of people from a mass of lived experiences, traditions and customs, backgrounds, and beliefs. As a pluralistic population of people will participate in a multitude of overlapping and concentric communities, there may be people in neighborhood communities who take part in different faith, cultural, professional, political, online, recreational, and other communities. The circumstances for how to pursue the good life for one person may differ from the circumstances for another.
In recognition of that, the common good (or at least part of it) consists of a justice system that protects the equal rights of everyone to pursue what is in their welfare, making a free society a good common to all people. A person’s exercise of his or her own judgement (while not infringing upon others from doing the same) in no way inhibits other people’s liberty. In fact, purposeful interaction commonly takes place within in a free society because it is believed to be mutually beneficial.
Communitarians neglect that just as a community is composed of individuals, improving the vitality of individuals necessarily improves the vitality of their communities. While individuals are best suited to live in a society, not just any kind of society will suit them. It must be a society that upholds the principles that people need when living in the company of others. The trouble with aggregating people into groups is that we inevitably lose track of information about the people who make up that group and thus the knowledge of how to promote their welfare. In contradistinction to communitarianism, individualism more successfully promotes community well-being by affirming the individuality of those change agent taking part in their communities.