Rep. Jeff Flake (R) acknowledged in a National Journal article last month that in the 1990s he worked as a lobbyist for Rossing Uranium, a mining company with ties to Iran, a position he kept relatively quiet. National Journal reported that Flake registered as a foreign agent during this period. In an interview with the Associated Press last week, Flake said he has been upfront about his work as a lobbyist for the mining company.
https://www.huffpost.com/entry/jeff-flake-lobbyist-bio-arizona-senate-race_n_1521522
Jeff Flake, John McCain, David Stringer=The Sierra Club
https://www.sierraclub.org/sites/www.sierraclub.org/files/sce/yavapai-group/Contacts.pdf