Garfield was certainly very smart...unfortunately his term was cut very short by either an assassin or a very bad Doctor, depending upon whom you ask.
I do believe it should be BOTH. Guiteau was the undoubted prime cause but the incompetent medical treatment (not just Doctors) was the unfortunate "coup de grâce!"
Read a biography of Garfield once. He had a party trick.
He’d get two pieces of paper and two pens.
Somebody would give him a Shakespeare or other quote.
He’d immediately translate and simultaneously write the quote down in Greek with his left hand, writing backwards, and in Latin with his right hand.
!!!