Appeals. A petitioner may appeal only from a final order issued by a federal habeas court. A petitioner wishing to appeal from an order denying habeas relief must apply for a certificate of appealability (COA) either from the district court judge who rendered the decision or from a circuit court judge. In the absence of a COA, a petitioner's notice of appeal of a district court order will be deemed by a circuit court to be a request for a COA. The petitioner must comply with the thirty-day deadline and other procedures that govern the filing of appeals. A district or circuit court judge may issue a COA only if the petitioner has made a “substantial showing of the denial of a constitutional right.” When issuing a COA, the judge must indicate the specific issues that satisfy the “substantial showing” standard. A court of appeals will overturn factual determinations of district courts only when those determinations are clearly erroneous.

In Hilton v. Braunskill, the Supreme Court established an equitable test for determining whether to release a prisoner pending appellate review of a district court's decision to grant the writ and discharge the prisoner. The factors to be considered include: (1) whether the applicant has made a strong showing of likelihood of success on the merits; (2) whether the applicant will be irreparably injured absent a release; (3) whether others interested in the proceeding will be substantially injured; and (4) whether the public interest would best be served by release. This test requires the appellate court to accord a presumption of correctness to the district court's custody decision.

The dismissal of a habeas petition on procedural grounds does not bar issuance of a COA. When the district court denies a habeas petition on procedural grounds without reaching the underlying constitutional claim, a COA should be issued if the petitioner shows that: (1) “jurists of reason would find it debatable whether the petition states a valid claim of the denial of a constitutional right”; and (2) “jurists of reason would find it debatable whether the district court was correct in its procedural ruling.”

A COA determination should be made in a separate proceeding, distinct from a decision on the merits of a petitioner's claim.