Digital advertisements used to interfere in the 2016 U.S. presidential election lacked disclaimers stating who paid for them. This was deliberate on the part of the platforms: Facebook and Google actively sought exemptions from mandatory disclaimer requirements that are standard for print and broadcast media. While prior research has placed blame squarely on the Federal Election Commission (FEC) for their lack of oversight of digital advertising, this paper demonstrates the way in which the platforms–Facebook in particular–engineered this regulatory failure in the form of capture on this specific issue. An analysis of documents submitted to the FEC demonstrates that Facebook and Google put profit ahead of the public interest in seeking exemptions from disclaimer requirements, refusing to change the size of their advertisements and downplaying the deceptive potential of political ads. Due to partisan gridlock and a lack of technological expertise, the FEC failed to rule decisively on exemptions or agree on alternative means of disclaimers for Facebook and mobile app ads, setting the stage for electoral interference in 2016. Implications for current regulatory efforts are discussed.