But such an individual may have sought a form of relief for which an aggravated felony conviction served as either an automatic or a discretionary bar. Compare, e.g., 8 U.S.C. § 1158(b)(2)(B)(i) (aggravated felony conviction bars grant of asylum) with § 1231(b)(3)(B) (aggravated felony conviction bars withholding of removal, a related form of relief, only when it has been determined to be a “particularly serious crime”); Matter of N-A-M-, 24 I.&N. Dec. 336, 342 (BIA 2007) (explaining that the determination of whether an offense is “particularly serious” so as to bar withholding of removal 12 turns on “a variety of factors” including “the nature of the conviction, the type of sentence imposed, and the circumstances and underlying facts of the conviction”). In addition, a rule that requires litigants to obtain and introduce evidence of the cause of the defendant’s deportation—likely resulting in disputed issues of fact requiring resolution—imposes a significant and unwelcome burden on appellate courts whose review is generally confined to the state court record below.