Re: Collusion conspiracy
If you do want to know why the FBI chose to include the Trump administration in their espionage investigation of Russian meddling in the election:
Such deals typically involve quid pro quo.
Russia benefits from having pro-Russian advocates in power in the U.S.
U.S. officials benefit from getting Russian assistance in winning their presidential campaign.
(and Russian blackmail, and Russian investments, gifts, money, etc.)
Russians factually assisted in the presidential campaign in favor of Trump.
The speculation, now this is a UUUUGGEE stretch of the imagination, is that people in the Trump campaign coordinated their factual attempts at winning the election, with the factual attempts by the Russians to help them win the election.
You are correct in that if they are smart, they would not have to leave a trail of any kind, to coordinate this way. If they are smart, they would only leave circumstantial evidence.
And there is a lot of circumstantial evidence, which is why there are investigations that include this.
Flynn - paid by Russians (and Turkey) in recent years, Flynn lies about speaking with the Russian government about sanctions. He was booted out of national security advisor position and is currently under investigation.
campaign chairman Paul Manafort and other members of his campaign, had repeated contacts with senior Russian intelligence officials during 2016,
Page: stated in 2017 he had no meetings with russian officials.
Two days later backtracked and said he "did not deny" having meetings with Russians. Oops
Roger Stone: Trump advisor - Admitted in March 2017 that he had been in contact with Guccifer 2.0 who is believed to be tied to the hacking of the DNC
Steel Dossier: Former MI6 official compiled an intelligence report based on Russian sources, and turned it over to the FBI. Claims Russia has blackmail on Trump from years back.
https://en.wikipedia.org/wiki/Russian_interference_in_the_2016_United_States_elections
So we'll see how deep Russian meddling goes, and we'll clean house of anyone dumb enough to get caught lying about it.
We likely won't find a smoking gun, because only idiots leave smoking guns on something that requires no gun at all.