As the controversy over critical race theory in public schools heats up, activists on both sides of the debate have spent massive amounts of time and money on a topic that takes aim at white privilege in America.

It’s the latest front in the culture war over how students should be taught U.S. history. Its roots date back to the early 1970s, but it has become a modern-day flashpoint that has moved from the classrooms into politics. Now, some are wondering who is funding the movement and why.