“(SOME) things would irreparably harm our ability to advance.”
In putting a bunch of pieces together then here is my take on that. There is a narrative that when the deep state did the U1 deal then they also sent some of the same Uranium to Iran. This Uranium was from the same batch and could be identified as such. So later in time the Uranium in Iran would be identified as having come from Russia even though it did not. This was going to be used somehow in order for Hillary and the deep state to start a war with Russia. Probably even WWIII. There is little doubt that John McCain has his hands in all of that too. Think about his trip to Syria where he met with terrorists. He was very deep state.
Assuming that narrative is true or even one similar to it then we have to think about the ramifications of officially confirming it. How would Russia react? How would the rest of the world react? The “USA” plotting something like that. No one would want anything to do with us. They could not even trust us.