had concerns about donald trump's call with the president of ukraine. he was also on the receiving end of yesterday's witness mr. vindman who went and saw him when he became concerned about that call and about some omissions perhaps from the transcript that far call. talk about these developments just in the last hour on capitol hill, phil. >> yeah, nicole, this is a big deal because both of these gentlemen you just talked about have the potential to deliver the most explosive testimony yet in the impeachment inquiry. bolton, because it is his job to run the national security process at the white house during this period, and he would be able to detail in very granular precise detail because of his rigor as a lawyer, because of the note-taking that he took in the government to be able to show how the process was irregular, how rudy giuliani was involved in ways he may not have been appropriate in bolton's review. we should remember that one of bolton's deputies fiona hill