Agree only to answer questions in writing.
David Kendal did that for Hillary. It was a whitewash. At least Pres. Trump now has a roadmap on how to phrase...”I don’t recall” a million different ways.
http://www.dailypress.com/news/dp-hillary-clinton-says-under-oath-she-can-t-recall-key-details-about-email-server-20161014-story.html
“Agree only to answer questions in writing.”
Exactly what I would do.
Trump will hurt himself if he communicates with the partisan Mueller in any manner shape or form. Mueller’s been taking with everyone close to Trump and now wants to talk to him. Remember Scooter and Flynn. Tell Mueller to pound salt.
My opinion is that you cannot compel the President of the United States to do anything. You can only impeach him.