In the 2000 case of Immigration and Naturalization Service v. Enrico St. Cyr, the U.S Supreme Court ruled in favor of St. Cyr, a lawful permanent resident who had pleaded guilty to a controlled substance violation that made him deportable under immigration law. The issue at hand was whether he could apply for discretionary relief from deportation - an option eliminated by two laws passed after his conviction but before his removal proceedings began: Antiterrorism and Effective Death Penalty Act (AEDPA) and Illegal Immigration Reform and Immigrant Responsibility Act (IIRIRA). The court held that these legislative changes did not apply retroactively to cases like St.Cyr's where plea agreements were entered into when such relief was still available. It further stated that denying habeas corpus review would raise serious constitutional questions as it is a fundamental safeguard against unlawful executive detention.

In the dissenting opinion for IMMIGRATION AND NATURALIZATION SERVICE v. ENRICO ST. CYR, Justice Scalia, joined by Chief Justice Rehnquist and Justices Thomas and O'Connor, argued that the majority misinterpreted both immigration law and habeas corpus jurisdiction to reach its decision. They contended that Congress clearly intended to eliminate judicial review of deportation orders with the passage of two laws in 1996: The Antiterrorism and Effective Death Penalty Act (AEDPA) and Illegal Immigration Reform Immigrant Responsibility Act (IIRIRA). According to them, these laws were designed specifically to expedite removal proceedings for criminal aliens like St. Cyr who had committed certain serious crimes. Furthermore, they disagreed with the majority's assertion that AEDPA or IIRIRA raised constitutional questions about suspending habeas corpus rights because neither act suspended such rights; rather they simply altered statutory procedures for challenging detention decisions.