Rubio was part of the team that vetted and presented the mining rights for aid swap that Zelensky was allegedly going to sign on Friday with Trump. The meeting/news conference unwound into the chaos we saw when Zelensky started to add conditions and terms and then attempt to box Trump in on commitments that had not been discussed before.

I'm thinking "Little Marco" may not have had enough negotiating experience to assess truthfully whether Zelensky really comprehended his own role in the negotiation. IE, he may have never put it to Zelensky "this is the actual deal you will present to Trump, and you won't add or change one word in it - agreed?"

I honestly think this got past Rubio. He looked like he was eating a plate of shit in that meeting, slumped back in a chair. The only person doing worse in that room was the Ukrainian ambassador, poor lady.