"Even the lesser burdens of a criminal investigation— including preparing for questioning by criminal investigators — are time-consuming and distracting. Like civil suits, criminal investigations take the President's focus away from his or her responsibilities to the people. And a President who is concerned about an ongoing criminal investigation is almost inevitably going to do a worse job as President."
Kavanaugh MN law review 2009
https://www.npr.org/2018/07/09/626164904/who-is-brett-kavanaugh-president-trumps-pick-for-the-supreme-court