$3.67bn will be spent on congressional elections this year, making it the most expensive mid-term election in US history

Up until recently this game had a limited number of players. Leaders from the two major US political parties, Republican and Democratic, controlled the money and devised the strategy.

Thanks to legislation and Supreme Court decisions over the past 12 years, however, the game has changed entirely. The power of political parties ebbed, while outside groups and individuals have been given new freedom to buy seats at the game.

They can run advertisements and develop get-out-the-vote organisations just like the parties did. And unlike their Republican and Democratic counterparts, they often have no caps on the funds they can raise and limited requirement to identify exactly where the cash comes from.



The result has been an explosion of money into the political system. According to projections by the Center for Responsive Politics, $3.67bn (£2.29bn) will be spent on congressional elections this year, making it the most expensive mid-term election in US history. In addition, independent expenditures are taking a larger and larger share of that total.