What crimes is the president suspected of committing?

Andrew McCarthy writes at National Review,

...Sessions recused himself from the Russia counterintelligence investigation, and then Deputy Attorney General Rod Rosenstein handed that counterintelligence investigation over to special counsel Robert Mueller. Consider how improper this is. Not only is Mueller invited to conduct a fishing expedition, with no specified crimes limiting his investigative jurisdiction, but counterintelligence probes are classified. Consequently, Mueller’s investigation proceeds in total secrecy: no boundaries on what may be examined, and no disclosures about what the special counsel is examining and why.

...Instead of badgering his attorney general on Twitter, perhaps the president could, you know, act like a president and instruct his Justice Department to comply with federal regulations. Sessions could be directed to consider whether his recusal complies with the regulation that limits disqualification to criminal investigations as to which there is a conflict. To the extent it does not, he should amend the recusal to conform to the regulation. Rosenstein could be directed to consider whether his appointment of a special counsel complies with the regulations that limit such appointments to criminal investigations or prosecutions as to which the Justice Department is conflicted. He could further be directed to specify exactly what potential crimes the special counsel is authorized to investigate.

Finally, after Rosenstein specifies the crimes, Mueller could be invited to seek an expansion of his jurisdiction if he can demonstrate that he has legitimately found evidence of other crimes. If this were done, if the regulations were followed, all of us, including the president, would know what crimes the president is suspected of committing . . . if there are any.

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