Trump must not be allowed to nominate the next Supreme Court justice until and unless he is exonerated by Mueller. There is a VERY good chance that the argument over whether a sitting president can be indicted will end up in the supreme court. We would not let any other defendant select his judge.
McConnell is an unscrupulous chode, and his hypocrisy is total, so lets ignore him entirely. There is a much more important principle at hand than playing tit-for-tat with lying jerks.