Whose law governs the scope of habeas relief under 28 U.S.C. § 2255(e) and § 2241

QUESTION PRESENTED Under 28 U.S.C. § 2255, a federal inmate can collaterally attack his sentence on any ground cognizable on collateral review, and in a “second or successive” petition on the basis of certain claims indicating factual innocence or relying on constitutional decisions made retroactive by this Court. 28 U.S.C. § 2255(h). Under 28 U.S.C. § 2255(e), an inmate can collaterally challenge his conviction through an “application for a writ of habeas corpus [under 28 U.S.C. § 2241]” whenever it appears “that the remedy by [§ 2255] motion is inadequate or ineffective to test the legality of his detention.” The question presented is whose law governs the scope of habeas relief under 28 U.S.C. § 2255(e) and § 2241. This question has two components. First, can a petitioner rely on an intervening circuit decision to trigger the savings clause? Second, does the substantive law of the petitioner’s confining circuit or convicting circuit govern the scope of habeas relief? (i)