Sometimes, in trying to get out of a mess, you get further stuck  into a new one.  This question and a few more about Trump’s ability to change the course of the  investigation, are answered by Politifact.com.   See link:

One year into Mueller probe, a review of attacks and key questions
By Louis Jacobson on Thursday, May 17th, 2018 at 10:10 a.m.

Stay tuned,

Dave