The Faretta Court explicitly held that an independent right to *self-representation* could be found in the structure and history of the sixth amendment, rather than suggesting that it "arises mechanically from a defendant's power to waive
the right to the assistance of counsel." Since the two rights are
independent, rather than mutually exclusive, from a constitutional
point of view there is no reason to demand that the defendant choose
one to the exclusion of the other as his *mode of representation*.

http://aulawreview.org/pdfs/25/25-4/homiak.pdf

The Swinton opinion makes a reference to the ability of counsel to adequately carry out the defense, that is, if the defendant cannot show the court a "compelling reason which would justify an exception to the normal *mode of representation* in a criminal trial, . . . the motion is . . . denied." United States v. Swinton, 400 F. Supp. at 807.

http://law.justia.com/cases/federal/district-courts/FSupp/41...