Can you provide a source verifying this claim?

Uhhh, me? I'm a leftist, a member of the DSA, a campaign volunteer, reader of leftist publications, and personally know a shit ton of leftists.

But you're free to see for yourself what leftist subs post about Russiagate. Here's a sampling:

/r/socialism:

• Leftist Critiques of Russiagate

• Russiagate Targets the Left: Liberal conspiracy theorists are using Russiagate to smear Bernie Sanders and Jill Stein. How long until they come for you?

• ‘Israeli Intervention In U.S. Elections Vastly Overwhelms Anything The Russians May Have Done’

• "Instead of championing universal healthcare, the Democrats are going to centre Russiagate in the midterms, achieve lacklustre results, after which the corporatist braintrust will conclude it was because they "moved too far to the left"

• Anyone else hate this DNC fueled Russiagate bullshit?

• Without buying into the media pushing Russiagate to shift the blame of the failures of American democracy onto a Russian spectre, there is potential that the FBI investigation could lead to a Trump impeachment in 2019. Here is a socialist analysis of those events surrounding the Trump administration

/r/Communism:

• Russiagate, the new McCarthyism

*A Review of Russiagate, its Propaganda and Hysteria

*'I just wish "Russiagate" would go away'

/r/chomsky:

https://www.reddit.com/r/chomsky/search?q=russiagate&restrict_sr=on&include_over_18=on&sort=relevance&t=all