It’s no secret that money plays an outsized role in American elections. The Federal Elections Commission estimates that Mitt Romney and Barack Obama spent some $7 billion in the 2012 presidential campaign, and that’s likely an undercount. Polls continually find that the US electorate thinks well-heeled interests drive policy.

But how, exactly, does big money structure elections?

No scholar has contributed more to our understanding of money in politics than Thomas Ferguson. Since the 1980s, in books like Right Turn: The Decline of the Democrats and the Future of American Politics and Golden Rule: The Investment Theory of Party Competition and the Logic of Money-Driven Political Systems, Ferguson has offered a powerful interpretation of US politics that focuses on the way the allegiances of various sectors of American business shape the party system.