"...He clearly crossed a line and can be objectively labeled an agent of a foreign power in the standard definition of the word. From the Russian perspective, it is a win-win even if the relationship doesn’t meet the cloak-and-dagger definition of a wholly clandestine espionage agent."

[justsecurity.org]

Elsewhere, analysis of Trump's life in New York and connections to the mob strongly suggest that Trump became a Confidential Informant for the FBI. It is possible Trump aided the FBI in takedowns of certain mafia characters. I received a rumor that reported how Trump knew when major drug shipments arrived in New York, but I haven't found any reference to this on the internet. In this time period, recall that some portion of the drug trade was conducted by CIA operatives seeking to obtain large amounts of cash for clandestine operations. Some of this comes from the Pentagon Papers, and some from the Mercury series on cocaine sold in the ghettos. (https://www.pbs.org/wgbh/pages/frontline/shows/drugs/special/cia.html

One may reasonably speculate that CIA operatives became cozy with the mafia to distribute the drugs they procured. It could be that Trump also developed a relationship with the CIA because of his connections with the FBI, the Italian mob, and then the Russian mob. As the Russian mob became an extension of Putin's government (mob), and began to groom Trump as an asset, the CIA may also have stepped in at some point to get a piece of the action. Thus, as a quasi-double agent/asset, Trump's megalomania gets a challenge and strokes he seeks. Mainly, Trump's activity, and finally, his political career, manages to get a pass from the CIA, and thus allowed to run for president. AND, this same CIA acts dumb about Trump's Russian dependency, and refuses to stop the candidacy of someone who is at least partly compromised. That's my theory.