Q: "You don't think this is dangerous to actually out the whistleblower? I mean the president has said that he's treasonous and a traitor."— The Hill (@thehill) November 6, 2019
Sen. Rand Paul: "I think that the 6th Amendment of the Constitution is very clear &... you should have the right to confront your accuser." pic.twitter.com/hE6NvbN3AS
Rand Paul knows that the 6th Amendment right to confront one's accuser only applies to witnesses who testify at trial. In an impeachment, that right would extend to the Senate trial. The Sixth doesn't apply to tipsters or anonymous sources who are not witnesses at trial. Police accept and even solicit anonymous tips all the time. If those tips lead to independent evidence of a crime, the anonymity of the tipster is legally irrelevant.
Rand Paul also knows about the importance of a whistleblower protections. In 2013, he was recognized for championing protections for federal whistleblowers.