(tiny boom)
IIRC, the basis for claiming that Manafort was lobbying the Trump campaign in favor of Russia, was a change in the GOP platform relating to the Russia/Ukraine situation.
Trump Directed Change To Party Platform On Ukraine Support : NPR
That the GOP platform was softened vis-a-vis Russia was totally fake news, as anybody actually reading the two versions of the GOP platform would find out.
What really happened with the GOP platform and Russia - Byron York.
The fake news was by the usual fake news purveyors, the prime media outlets, and coincided with the rise of the "Russian collusion" myth. The correction was actually fairly prompt, Byron York's article just happens to be one of the best historical summaries.
Just saying, Gates' testimony isn't much of a bombshell to those who noticed the MSM stories as fake news to begin with.