What is the test for determining whether a defendant is competent to stand trial?

We review a district court's determination not to order a competency hearing sua sponte for abuse of discretion. United States v. Quintieri, 306 F.3d 1217, 1232-33 (2d Cir. 2002). The Fourteenth Amendment's Due Process Clause "prohibits the criminal prosecution of a defendant who is not competent to stand trial." Id. at 1232 (citation omitted). A court shall order "a hearing to determine the mental competency of the defendant" "if there is reasonable cause to believe that the defendant may presently be suffering from a mental disease or defect rendering him mentally incompetent to the extent that he is unable to understand the nature and consequences of the proceedings against him or to assist properly in his defense." 18 U.S.C. 4241(a). This is a "highly particularized assessment that varies in each case." United States v. DiMartino, 949 F.3d 67, 71 (2d Cir. 2020) (internal quotation marks omitted). As such, "we afford district courts wide latitude to reach conclusions as to both 'reasonable cause' and a criminal defendant's overall competence to stand trial." United States v. Arenburg, 605 F.3d 164, 165 (2d Cir. 2010).