Campaign finance is often seen as a murky, controversial world that helps bankroll ever-lengthening presidential races.
Political Action Committees, or PACs, and their later iteration, super PACS, dominate the campaign finance funding now, but that wasn't always the case.
The beginnings of PACs date back to unions and how they initially directed portions of their members’ dues towards political campaigns, but after that spending plan got squashed, they later created PACs as the way around the new law.
Limits were then put on PACs in the 1970s, effectively leading to the rise of super PACs with another work-around.
Learn more about the evolving role of campaign finance in the video above.