Common Cause filed complaints with the Department of Justice (DOJ) and the Federal Election Commission (FEC), alleging reason to believe that Cambridge Analytica LTD and its sister company, SCL Group Limited, and numerous employees of the London-based companies repeatedly violated the prohibition on foreign nationals performing certain election-related activities over two U.S. election cycles – including extensive work for the Trump campaign.

On March 5, 2018, Common Cause filed complaints with the Department of Justice (DOJ) and the Federal Election Commission (FEC) alleging reason to believe that President Trump and his campaign violated numerous federal campaign finance laws by setting up super PAC America First Action (AFA) and dark money group America First Policies (AFP) to raise and spend unlimited "soft money" to influence federal elections, including President Trump's 2020 reelection efforts. The March 2018 complaint also alleges Vice President Pence and his leadership PAC, the Republican National Committee (RNC), and a number of aides violated numerous campaign finance laws by coordinating “soft money” fundraising and spending with AFA and AFP. On March 15, 2019, Common Cause filed supplements with the DOJ and FEC to its 2018 complaints, providing further evidence of campaign finance law violations in the form of the Trump campaign's public endorsement of AFA as the campaign's "approved" outside group and solicitation of funds for the group.