Whether a defendant's guilty plea was knowing and voluntary when the defendant was not informed of an element of the offense

QUESTION PRESENTED Petitioner Frank Trujillo pleaded guilty to one count of knowingly possessing a firearm after having been convicted of a crime punishable by imprisonment for a term exceeding one year, in violation of 18 U.S.C. §§ 922(g)(1) and 924(a)(2). At the time of his plea, he did not understand that knowledge of his status at the time of the offense was an element of the crime. See Rehaif v. United States, 139 S. Ct. 2191 (2019). On appeal, he argued for the first time that his plea should be vacated because it was not knowing and voluntary, in violation of the due process clause. The following question is presented: When a defendant argues for the first time on appeal that his guilty plea was not knowing and voluntary because he was not informed of the elements of the offense, what standard of review applies? i