The Assistance of Counsel Clause in the Sixth Amendment is rather clear.
LOL it certainly is: You enjoy the right to have the assistance of counsel for defense. Until 1963, however, everyone interpreted that to mean you could do so if you so chose. But even giving that away - I think the idea that lawyers should defend anyone, by any means, destroying any reputation, by manipulating emotion rather than sticking to fact, by lying, by coaching witnesses, etc., is odious. Same goes for DA’s.