[The Hill] Glenn Greenwald, a leftist, offers his perspective on the man the FBI selected to spy on the Trump campaign and on the brouhaha surrounding his "outing." First, Greenwald says that this man, now a professor, was responsible for spying on the Carter administration on behalf of Ronald Reagan’s presidential campaign in 1980. He did this, by running a scheme whereby CIA operatives passed classified information about Carter’s foreign policy to Reagan campaign officials in order to ensure the Reagan campaign knew of any foreign policy decisions Carter was considering.If true, this means, that (in Greenwald’s words) "the informant used by the FBI in 2016 to gather information on the Trump campaign was not some previously unknown, top-secret asset whose exposure as an operative could jeopardize lives." Rather, "his decades of work for the CIA ‐ including his role in an obviously unethical if not criminal spying operation during the 1980 presidential campaign ‐ is quite publicly known." Indeed, it can be discover from public records showing him to be a CIA "vendor."
Related and a MUST read: The Last Refuge - Stefan Halper Agent Provocateur – In His Own Words…
Related at the Intercept - The FBI Informant Who Monitored the Trump Campaign, Stefan Halper, Oversaw a CIA Spying Operation in the 1980 Presidential Election