Judith Baker (debtor) bought a car and obtained a certificate of title in New Mexico. Primus Financial Services (creditor) financed the purchase. Primus perfected its security interest in New Mexico. Baker moved to Wisconsin and did not obtain a Wisconsin certificate of title for the car; the New Mexico title remained effective. Baker filed for bankruptcy. The trustee of Baker’s bankruptcy estate claimed that Primus was required to reperfect its security interest in the car in Wisconsin. The bankruptcy court disagreed and ruled in favor of Primus. The district court affirmed. The trustee appealed.