On application for a writ of _habeas corpus_, the Court may either issue the writ, and, on the return, dispose of the case, or it may waive the issuing of the writ and consider whether, upon the facts presented in the petition, the prisoner, if brought before it, could be discharged.[1451] The proceeding may not be used to secure an adjudication of a question which, if determined in the prisoner's favor, could not result in his immediate release.[1452] A discharge of a prisoner on _habeas corpus_ is granted only in the exercise of a sound judicial discretion.[1453] While the strict doctrine of _res judicata_ does not apply to this proceeding,[1454] the Court may, in its discretion, dismiss a petition for _habeas corpus_ where the ground on which it is sought had been alleged in a prior application, but the evidence to support it had been unjustifiably withheld for use on a second attempt if the first failed.[1455] Where the Government did not deny the allegation in a prisoner's fourth petition for _habeas corpus_, but sought dismissal of the proceedings on the ground that the prisoner had abused the writ, the prisoner was held to be entitled to a hearing to determine whether the charge of abusive use of the writ was well founded.[1456] Suspension of the Privilege A critical question under this section is who determines with finality whether the circumstances warrant suspension of the privilege of the writ. In England the writ may be suspended only by Act of Parliament,[1457] and in an early case Chief Justice Marshall asserted that the decision as to when public safety calls for this drastic action depends "on political considerations, on which the legislature is to decide."[1458] At the beginning of the Civil War Lincoln authorized the Commanding General of the Army of the United States to suspend the writ along any military line between Philadelphia and Washington.[1459] In Ex parte Merryman,[1460] Chief Justice Taney strongly denounced the President's action and reasserted the proposition that only Congress could suspend the writ. Attorney General Bates promptly challenged Taney's opinion. Noting that in Ex parte Bollman, Marshall did "not speak of suspending the _privilege_ of the writ, but of suspending the _powers vested in the Court_ by the act," he took the position that the constitutional provision was itself the equivalent of an Act of Parliament.[1461] Thereafter, by an express provision of the act of March 3, 1863, Congress declared, "That, during the present rebellion, the President of the United States, whenever, in his judgment, the public safety may require it, is authorized to suspend the privilege of the writ of _habeas corpus_ in any case throughout the United States, or any part thereof."[1462] The validity of this statute was assumed in Ex parte Milligan,[1463] but a narrow majority of the Court declared that the suspension of the writ did not authorize the arrest of any one, but