At trial
The presence of a defendant in a criminal trial is guaranteed by the United States and Montana Constitutions. ("In all criminal prosecutions, the accused shall enjoy the right . . . to be confronted with the witnesses against him . . ." U.S. Const. amend. VI. "In all criminal prosecutions the accused shall have the right to appear and defend in person and by counsel . . ." Mont. Const. art. II, § 24.). Whether a criminal defendant's right to be present at a crucial stage of trial has been violated is a question of constitutional law, and review of constitutional law by the Montana Supreme Court is plenary. State v. St. Germain, 2007 MT 28, ¶ 14, 336 Mont. 17, 153 P.3d 591.
Other proceedings
The presence of a defendant in non-trial stages of criminal proceedings may be regulated by statute. See Title 46, MCA. A district court's interpretation and application of a statute is reviewed for correctness. State v. Clark, 2006 MT 313, ¶ 7, 335 Mont. 39, 149 P.3d 551.