did not explicitly prescribe the temporal reach of IIRIRA, we must determine whether application of IIRIRA to Molina would “impair rights a party possessed when he acted, increase a party’s liability for past conduct, or impose new duties with respect to transactions already completed.” 511 U.S. at 280, 114 S.Ct. 1483. If a statute merely changes “procedural rules” and does not affect “substantive rights, liabilities, or duties,” it will not have an impermissible retroactive effect. Id. at 275, 278, 114 S.Ct. 1483. In Alvarez-Portillo v. Ashcroft, we concluded that IIRIRA had an impermissible retroactive effect on the petitioner because it denied him the ability to argue affirmative defenses to removal. 280 F.3d 858, 867 (8th Cir.2002), overruled on other grounds b 4 (11th Cir.2004) (<HOLDING>); Arevalo v. Ashcroft, 344 F.3d 1, 14 (1st
holding parent entitled to credit for any social security disability benefits paid to child as a result of parents disability holding that a denial of due process warrants mandamus relief holding imposition of new legal liabilities for past conduct was retroactive holding evidence of a 13 permanent partial disability insufficient to establish disability for purposes of ada holding iiriras denial of ability to apply for relief created a new disability and was impermissibly retroactive