https://thinkprogress.org/nixons-justice-department-warned-that-the-president-can-t-pardon-himself-f70228c8b9ef
"This decades-old memo is likely to take on new significance, as another president caught up in a criminal investigation reportedly is considering a self-pardon. The Washington Post reported Thursday evening that Donald Trump “has asked his advisers about his power to pardon aides, family members and even himself in connection” with special counsel Robert Mueller’s investigation into the Trump campaign’s Russian connections."