http://thefederalist.com/2018/02/13/clintons-behind-whole-trump-russia-collusion-story/
So Here's the Quick and Dirty Summary
Piecing all this together is difficult, but the broad strokes are as follows:
Much of the Trump-Russia collusion evidence comes from the Steele dossier.
The Steele dossier was created during the 2016 election, at the behest and funding of Democrats and Hillary Clinton's campaign.
Grassley and Graham's memo and Winer's op-ed show Steele was given some information from at least one source tied directly to the Clintons.
The FBI is likely using a second dossier in its investigation, one authored by Cody Shearer.
Shearer has close ties to Blumenthal and the Clintons.
Top officials at the FBI and Department of Justice, including members of the team working on the Trump-Russia collusion investigation, had ties to the Democratic Party; or the dossier; or expressed their dislike of Donald Trump, a conflict of interest for their work; or all three. For instance, DOJ official Bruce Ohr's wife worked for Fusion GPS, which paid Steele to make the dossier while it was being created.
The FBI used the Steele dossier and maybe even information from Shearer to get a FISA warrant to spy on the Trump campaign team, but it failed to tell the FISA court of the dossier's connection to the Clintons or that Blumenthal's information reached Steele.
The vast majority of "evidence" supposedly linking Trump to Russia resulted directly or indirectly from the FISA warrant and the investigation that followed.