Giuliani has made this point: at a minimum for a special counsel to be appointed there must be evidence of a crime.

“Under federal regulations governing his appointment, evidence of a suspected crime is a necessary predicate. It never happened. Instead, Mueller was granted broad authority to investigate matters that are not necessarily criminal at all. A special counsel is not authorized to search for a crime; there must be evidence of a crime first. This did not exist, rendering Mueller’s appointment illegitimate and invalid. The authorization order itself was defective inasmuch as it did not set forth the required “specific factual statement” of a defined crime."

https://www.foxnews.com/opinion/2018/09/18/gregg-jarrett-if-rod-rosenstein-defies-trumps-order-to-declassify-documents-should-be-fired.html