McCardle reinforced Congress' constitutional right to determine in which cases, and under what rules, the Supreme Court may carry out its appellate responsibilities. Yet the majority opinion proved that the Court can find ways to avoid excessive oversight.

McCardle was a Vicksburg, MS, newspaper editor arrested under the Reconstruction Act for printing articles libelous of the federal reconstruction authorities. Under the Act, McCardle would be tried by military tribunal, rather than civilian courts. In Ex parte Milligan, decided the year before McCardle's arrest, the Supreme Court had struck down the use of military tribunals in civilian cases where proper civilian remedies were available. McCardle challenged his detainment on the basis of this decision, and requested a writ of habeas corpus (release from unlawful detention) from the federal courts.

Rejected by the lower courts, McCardle then applied directly to the Supreme Court which, under the Habeas Corpus Act of 1867, was allowed to hear appeals claiming detention in violation of constitutional rights.

Political feelings over the entire concept of Reconstruction ran high. Obviously the defeated South, overwhelmingly Democratic, found it to be profoundly humiliating and, in their view, unconstitutional. The Republicans on the other hand, whose program it was, feared that any review of the Reconstruction Act by the Court would threaten the effort. In bringing his case for a writ of habeas corpus McCardle must, by definition, ask the Court to consider the constitutionality of the Act itself.

Article III Section 2 of the Constitution provides to Congress the right to determine which cases the Supreme Court shall hear, and the rules under which it will operate, in its appellate jurisdiction. (Congress does not have that right in the Court's original jurisdiction cases, as was hammered home in Marbury.)

To head off the threat to its reconstruction program, the Republican controlled Congress used its Article III power to rescind the authority granted the Court by the Habeas Corpus Act to hear appeals for the writ. Although Congress began its action after the Court had heard arguments in the case, the majority agreed to withhold its decision until congressional action was completed, especially since the Court's current term was due to expire.

When it returned for the 1869 term, the Court accepted the decision of Congress to rescind its power in appeals for habeas corpus, and dismissed McCardle. It no longer had jurisdiction to hear the case.

The Court was generally viewed as overly submissive to the harsh realities of Reconstruction, and McCardle is often accepted as supporting that position. But, as Chief Justice Salmon Chase pointed out, while Congress rescinded the specific power relied upon by McCardle in bringing his case, the Court still retained broad powers under the Judiciary Act of 1789, including the power to issue original writs of habeas corpus in federal cases. This observation is often seen as a reminder to Congress that the Court will not be easily constrained.