Michelle Ye Hee Lee Craig Timberg The Washington Post

Two years before helping Donald Trump target prospective 2016 supporters, the now-embattled data firm Cambridge Analytica tested its tools with an array of conservative groups allied with the wealthy Mercer family, including a super PAC run by newly appointed national security adviser John Bolton.

Two years before helping Donald Trump target prospective 2016 supporters, the now-embattled data firm Cambridge Analytica tested its tools with an array of conservative groups allied with the wealthy Mercer family, including a super PAC run by newly appointed national security adviser John Bolton.