In Brown v. Allen, 344 U.S. 443, 73 S.Ct. 397, 97 L.Ed. 469 (1953), the Court considered the statutory requirement, under 28 U.S.C. 2254 that a petitioner exhaust his state remedies before applying for federal habeas corpus relief. The Court concluded that Congress had not intended 'to require repetitious applications to state courts.' 344 U.S., at 449, n. 3, (73 S.Ct. 397.) The Court declined to rule that the mere possibility of a successful application to the state courts was sufficient to bar federal relief.