In this chapter I expose how direct democracy instruments based on the ballot (referendum, popular initiative, recall), as opposed to assembly based direct democracy, have developed in Switzerland and have been adopted by more than 20 US states as an answer to specifically urban challenges. I present new evidence from a quantitiative analysis of the Google Books corpus tracing the reference to Swiss direct democracy in American political literature at the turn of 19th and 20th centuries, supporting this diffusion.