Welcome to Pushback. I'm Aaron Matte. In 2016, Rick Gates served as the deputy chair of the Trump campaign for president.

But since then, he has played a much different role on the national stage. In October 2017, Rick Gates was indicted as part of Special Counsel Robert

Mueller's Russia investigation. And from that point forward, Rick Gates has played a central

role in the nonstop conspiracy theories and innuendo about a possible Trump-Russia plot.

Many media outlets speculated that Rick Gates would be the one to deliver the smoking

gun of collusion.

Tonight for the first time, CNN is learning that a key figure in the investigation,

a figure who is a cooperating witness, we should point out, is helping Mueller make the

collusion case.

Now, I want to underscore those two words. He's helping.

That witness is Rick Gates.

And what are you learning about Rick Gates and what Mueller wants from him?

What he needed Gates' help with was the core mission of the special counsel, which is

the ties between Trump campaign and alleged ties between the Trump campaign and Russians and Wolf.

What this means is that the special counsel is looking specifically at making the case of Russian collusion.

What Gates was in a front row seat to see, what he was part of with a better vantage point than almost anybody else on earth,

was the central question of what was actually

going on between the Trump campaign and Russia.

And now he's Mueller's star cooperating witness.

Tada.

Well, we all know how it turned out.

The Mueller investigation found no conspiracy between Trump and Russia, but that hasn't stopped

...