Dark Money in politics was caused by two Supreme Court decisions. Buckley vs. Valeo (1976) restricted the those subject to election finance laws, and Citizens United vs. FEC (2010), which allowed corporations and other groups to donate to elections. Together these decisions allowed donors to give money to support a candidate or party without giving their name. These secret donations, or "dark money" donations, have in the last few years climbed to hundreds of millions of dollars.
Democrats have unsuccessfully tried several times to pass a law outlawing secret donations. They believe the voters should know who is donating to political campaigns. But Republicans have blocked all attempts to stop dark money donations and shine a light on all donations. They refused to vote to stop it because they believed that most of the dark money went to support campaigns in their party.
They were right. In the past, almost all dark money went to support the election of Republican candidates.
But that was in the past. In 2020, things changed. As the chart above shows, in the last election most dark money went to help Democratic candidates -- over twice as much as went to Republican candidates.
Democrats received and spent about $514 million in dark money in 2020. Republicans received and spent only $204 million in dark money.