Sunday on CBS News’ “Face The Nation,” Sen. James Lankford (R-OK) said the anti-Trump texts sent by FBI agent Peter Strzok did not taint FBI special counsel Robert Mueller’s entire investigation.

Partial transcript as follows:

JOHN DICKERSON: Let me ask you about the texts that were released this week from an investigator on the Mueller team. What’s your opinion about those texts, one of which referred to an insurance policy? There’s a lot of debate about that text and what exactly was meant by it. But how serious do you think this is in the context of the larger investigation that you know something about?

JAMES LANKFORD: I think it’s serious any time you have an investigator within an investigation that has an obvious political bias whichever direction that goes. It’s clear this individual within the Mueller team that was also on the Clinton email investigation team on the F.B.I. in their leadership had a strong bias against now-President Trump when he was Candidate Trump and was very clear about that. When that was discovered by the Mueller team, they fired him, appropriately so, and took him off of that team. But that is a big consideration. We expect the Justice Department to be blind and be fair to all sides, not have a clear political bias and express it so strongly.

JOHN DICKERSON: But given that Mueller took him off the investigation, do you think this taints the larger project he’s doing since you know the scope of that larger project?

JAMES LANKFORD: Yeah, it’s very serious to be able to have someone inside. What they’ve got to determine is: was he directing the investigation one way or the other while he was on the investigation? Is that something they can go back, and repair, and look, and see if there’s any kind of bias that’s in it? Obviously, I don’t think it taints the entire process. But it certainly taints that season of it. And it’s something you should look at with any political investigation that he was on at the time. Again, we want our F.B.I. agents to be neutral and to be non-political. Not very actively engaged politically.