Does a defendant have a right to be present at trial?

Further, we note that a defendant has the right under the Sixth Amendment to be present throughout his criminal trial. Lewis v. United States, 146 U.S. 370, 373, 13 S.Ct. 136, 137, 36 L.Ed. 1011 (1892). Nonetheless, if he knowingly insists on misbehaving at trial to such an extent that his conduct is unduly disruptive, the trial judge ordinarily has the power to have him removed from the courtroom and to continue the trial in his absence until he promises to behave properly. See Illinois v. Allen, 397 U.S. 337, 346, 90 S.Ct. 1057, 1062, 25 L.Ed.2d 353 (1970). The premise of this power is that the defendant who knowingly and voluntarily chooses to so misbehave waives his right to be present at trial. When the defendant's misconduct is the result of a mental disease or defect, however, he cannot be said to have made an intelligent and voluntary choice. Cf. Pate v. Robinson, 383 U.S. 375, 384, 86 S.Ct. 836, 841, 15 L.Ed.2d 815 (1966) ("it is contradictory to argue that a defendant may be incompetent, and yet knowingly or intelligently 'waive' his right to have the court determine his capacity to stand trial"). Thus, if the trial court were to conclude that the defendant's unduly disruptive behavior resulted from a mental disease or defect and was beyond his rational control, it would be forced to suspend or abort the trial. See Drope v. Missouri, 420 U.S. at 181-82, 95 S.Ct. at 908. These factors may properly be taken into account by the court in a pretrial competency hearing.