How do the economy and politics separate people?
Politics and the economy separate people by dividing them into groups with certain characteristics. In politics, you have (for example) evangelical Christians who are most interested in social issues, economic conservatives who care most about lowering taxes, Tea Party people who want to reduce the size of government, and various forms of Democrats and liberals and moderates. Politics has separated people into these groups.
Economically, the splits are a little more obvious. Our economy allows for a great deal of income inequality and, thereby, splits us into rich, poor, and middle class. We are also split to some degree by the prestige of the jobs that we occupy.
In these ways, politics and the economy split us up into somewhat distinct groups.