New claims in prison appeals

Where a state prisoner has yet to be provided with “one fair opportunity” to litigate the merits of a claim of constitutional error in federal court even after the district court entered its judgment with respect to the state prisoner’s habeas petition, and the §2254 petition is pending on appeal in the circuit court, should an exception to this Court’s Rivers rule be recognized to allow a petitioner to move to remand his §2254 habeas petition to the district court and to amend his §2254 habeas petition under Federal Rule of Civil Procedure 15, rather than forever being denied one fair opportunity to litigate the claim of constitutional error because the amended petition is considered a second or successive petition for § 2244(b) purposes, and the claim presented in the amended petition is considered one that was presented in a prior habeas application that “shall be dismissed” under §2244(b)(1)?