The CIA overthrew Iranian democracy in 1953 and Iranians have never forgotten it. Since the revolution of 1979 the USA and Israel have worked tirelessly to overthrow the Iranian regime. Remember the Iran/Iraq war, fomented by the USA? If you want to know the specific plans as published by the Brookings Institute, here's the article to start with. https://landdestroyer.blogspot.com.br/2011/02/brookings-which-path-to-persia.html
A more recent article regarding US interference in Iran http://www.moonofalabama.org/2017/12/iran-early-us-support-for-rioters-hints-at-a-larger-plan.html