Rubio says: "We're going to wait till we get more facts."

https://www.rubio.senate.gov/public/index.cfm/press-releases?ContentRecord_id=354445F8-274A-4D24-8287-ED56BB31E3A2

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Martha MacCallum: “What about what he did admit to — the president. He said yes he did bring up Joe Biden and the possibility of an investigation on the phone with him, and obviously he’s the frontrunner, at least at this point, in the 2020 election. Do you have any problem with him bringing that up with the Prime Minister of Ukraine?”

Rubio: “I don’t think he should’ve done that. And I’ve said that. But that’s not what they’re saying. What I’m hearing voices out there saying is not only did he bring it up, but there was a quid pro quo. Well, there’s no evidence of that. Maybe there will be, but right now there isn’t. Look this is not something you throw around lightly. You know, we’ll see what the facts are. I’m not taking a position one way or the other. The position I’ve taken right now is we want to know facts. We want to see the transcript of that call. We’re going to wait till we get more facts. We have both of those relevant individuals coming in the Intelligence Committee that I sit on and that’s what this should be based on.”