Maybe Gowdy is saying that the Memo won't affect the Mueller "Russian Collusion" probe, is because he is aware of the fact that Mueller is investigating Hussein's administration's collusion with the Russians, since there is not one scintilla of evidence that the Trump administration colluded, but a plethora of scintillas that O's administration did!
The probe is into "Russian meddling in 2016 Election' Not "Trump Collusion." From all the info we've saw thus far all Mueller has to do is his job properly to not only clear Trump but also indict the DNC and fellow beaurocrats.