Liberal Super PACs spent twice as much as conservative Super PACs in federal races in 2013, according to a Center for Responsive Politics tally of independent spending.
The liberal Super PACs spent $10.8 million despite condemnation of outside money from congressional Democrats and President Barack Obama, USA Today reports.
Seventy percent of election-related "dark-money" spending was liberal money. The money came from unions and billionaires Tom Steyer and Michael Bloomberg.
